|Year : 2016 | Volume
| Issue : 5 | Page : 29-61
|Date of Web Publication||7-Nov-2016|
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
. Poster Presentation. Indian J Nucl Med 2016;31, Suppl S1:29-61
| Instrumentation and Medical Physics|| |
Comparison of radiation dose received by patients in noncontrast computed tomography and contrast-enhanced computed tomography during integrated positron emission tomography/computed tomography
Ashutosh Pandey, Sukanta Barai, Sanjay Gambhir
Department of Nuclear Medicine, Division of PET Imaging, SGPGIMS, BBA Central University Lucknow, Uttar Pradesh, India
Objective: The purpose of this study is to compare the radiation dose of patients during noncontrast computed tomography (NCCT) and contrast-enhanced computed tomography (CECT) in integrated positron emission tomography/computed tomography (PET/CT). Methods: Twenty-five patients who underwent both NCCT and CECT in integrated PET/CT examination were included in this study. The dose from NCCT and CECT investigations evaluated based on solid thermoluminescent dosimeter crystal placed on brain, right lung, liver, and mid-thigh. After this, we compared patients' radiation dose during NCCT and CECT. Results: An increase in radiation dose was seen in CECT study as compared with NCCT study in all organs studied. Average dose increments were 3.5% for brain, 4.58% for right lung, 3.60% for liver, and 4.25% for mid-thigh. The P value for brain is 0.001, which is statistically significant. The P value of liver, right lung, and mid-thigh is not statistically significant. Finally, CECT study compared to NCCT shows significant increase in radiation dose. Conclusion: The PET/CT acquisition protocols examined in this study reflect the range of NCCT and CECT in four regions of body, i.e., brain, right lung, liver, and mid-thigh, respectively. A clear significance was only showed in brain. It was also noticed that the radiation dose increases in CECT compared to NCCT. Hence, patient dose reduction is prime concern and it is need to optimize the reduction in radiation dose without compromising on the diagnostic findings.
Role of postreconstruction Gaussian filter in positron emission tomography scan
Sachin Tayal, Arun C. Gandhi
Kailash Cancer Hospital and Research Centre, Vadodara, Gujarat, India
Objective: To study the effect of Gaussian filter on image quality and study the change in mean standardized uptake value (SUV) of a photopenic lesion in a background of high fluorodeoxyglucose (FDG) uptake. Methods: Fusion positron emission tomography (PET)/computed tomography imaging of brain was performed on GE's Discovery STE model on a patient with history of metastatic carcinoma of the left breast. Images were acquired 60 min after intravenous administration of 8.41 mCi of F-18 FDG. Informed consent was obtained before performing the PET scan. Data were acquired in list mode for 10 min in a single-bed position in 128 × 128 matrix. The images of the study were reconstructed with ordered subset expectation maximization algorithm with 2 iterations and 28 subsets. A large photopenic area was noted in right parietal lobe of the patient. Postreconstruction Gaussian filter of 2, 4, 6, 8, and 10 mm in full width at half maximum (FWHM) was applied retrospectively to the acquired data. The mean SUV value in g/ml of the photopenic lesion was measured in respective images of varying FWHM Gaussian filter and subsequently mean SUV value of a second region of interest, drawn over the adjacent comparative hot area was evaluated to compare the effect of smoothing with increasing width of Gaussian filter. Results: The image applied with 6 mm FWHM Gaussian filter showed a higher quality image, with a balance of sharpness of the edge and smoothing effect. Images reconstructed with <6 mm FWHM of Gaussian filter were comparatively grainy and lacked the proper defined edges whereas the images reconstructed with greater than 6 mm resulted in over smoothing and hence gradual increase of mean SUV in the photopenic lesion and vice versa in adjacent hot area. Conclusion: The Gaussian filter used in PET scan to blur images and remove noise should be used optimally when studying a photopenic lesion in a background of high FDG uptake, in order to get useful clinical images.
Automated synthesis and quality control of (18 F)-fluorothymidine: A trick to fix
Srishti Varma, Priya Saxena, Sandeep Singh, Manish Dixit, Sanjay Gambhir
Department of Nuclear Medicine, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
Objective: 3'-deoxy-3'-(18 F)-fluorothymidine or (18 F)-FLT as a PET imaging agent to provide a surrogate biomarker of DNA replication. As an antimetabolite of the endogenous nucleoside thymidine, (18 F)-FLT uptake in tissue reflects activity of the thymidine salvage pathway, a mechanism that provides DNA precursors from the extracellular environment to dividing cells. (18 F)-FLT PET studies have been used in oncology and other highly proliferative tissue. Methods: In our newly established cyclotron facility having Sumitomo Heavy Industries HM-18 cyclotron for the production of variety of radioisotopes such as F-18, I-124, Cu-64, N-13, and C-11, we synthesized the fully automated production of ( 18 F)-FLT using Sumitomo's multipurpose synthesizer. The 3-N-BOC-5'-O-dimethoxytrityl-3'-O-nosyl-thymidine was chosen as precursor for 18 F-FLT. The final purified product was isolated after HPLC purification. The purity of final product was performed with battery of quality test. Results: The overall uncorrected radiochemical yield was 14% ± 7% with radiochemical purity ≤97%. Total synthesis time was 45 min. Conclusion: This automated nucleophilic procedure allows (18 F)-FLT synthesis with high reproducibility with good radiochemical yield as well as purity that is mandatory for future clinical application.
Comparative evaluation of 24-h I-131 thyroid uptake between gamma camera-based method using high-energy collimator and standard uptake probe-based method
Devesh Chandra Bhatt
Department of Nuclear Medicine, Oncology Building, Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
Objective: To make a quantitative comparison between 24-h thyroid uptake calculated by Gamma camera-based and thyroid uptake probe-based methods after administration of a diagnostic I-131 dose in patients with benign thyroid disorders. Methods: This study group comprised 20 patients, of which 8 patients were male and 12 patients were female (age range 25-50 years). These patients had benign thyroid disorders and most of whom had been referred for thyroid evaluation before I-131 treatment. A liquid form of I-131 (50 iCi [1.85 MBq]) was administered to patient with adequate flushing of vial to ensure maximum oral administration of dose. The dose was prepared by the help of pipetting technique. I-131 uptake was measured at 25 cm distance from the face of the crystal to the anterior neck or phantom and also 24 h thyroid uptake was calculated using a probe-based method and a camera-based method with a high-energy parallel hole collimator. Results and Discussion: Radioiodine uptake was measured by gamma camera, and uptake value was 50% of that measured by thyroid uptake probe in 19 patients of 20 patients. Therefore, by applying a correction factor, we can equate the uptake value of probe method and gamma camera method. Conclusion: On the basis of precision in counting by thyroid uptake probe, it takes the edge over gamma camera method; therefore, gamma camera method can never be an ideal substitute. Hence, thyroid uptake probe method cannot be replaced by gamma camera method.
In vivo imaging of integrins in pulmonary thromboembolism using 99m Tc-diethylenetriaminepentaacetic acid-bis-c(RGDfK) as a single-photon emission computed tomography tracer
Ankita Pandey, Puja Panwar Hazari, Jurgen Schulz, Anil K. Mishra
Division of Cyclotron and Radiopharmaceutical Sciences, Institute of Nuclear Medicine and Allied Sciences, DRDO, New Delhi, India
Aim: Intravascular thrombosis is the major cause of morbidity and mortality worldwide. Patients at risk of pulmonary embolism frequently undergo thoracic computed tomography (CT) as part of the assessment for other cardiopulmonary conditions. Activated platelets are the key participants in thrombotic disorders. A number of integrins such as aIIBb3, avb3, a2b1, a5b1, and a6b1 are known to participate in thrombus formation. Both avb3 and aIIBb3 receptor ligands share a common RGD tripeptide binding sequence. We have previously demonstrated that 99m Tc-DTPA-bis-c(RGDfK) is an excellent scintigraphic agent for imaging of avb3 receptors being expressed in abundance in malignant glioma and melanoma cancer. Therefore, the present study is primarily aimed at the development of 99m Tc-labeled homobivalent DTPA-bis-c(RGDfK) conjugate and its preclinical evaluation in animal models of pulmonary thromboembolism. Materials and Methods: Homobivalent DTPA-bis-c(RGDfK) was radiolabeled with 99m Tc. The conjugate was subjected to in vivo single-photon emission computed tomography-computed tomography (SPECT-CT) analysis in the mouse model of collagen epinephrine-induced pulmonary thromboembolism to assess its thrombus binding capability and specificity. SPECT and CT were used to show accumulation of bivalent DTPA-bis-c(RGDfK) with high and specific uptake in the thrombus rich regions in lungs. Results: Pharmacokinetic and biodistribution studies confirmed long circulation times (t1/2 [fast] =35 min and t1/2 [slow] = 5 h) and efficient accumulation in thrombus. Biodistribution studies in the mouse model of pulmonary thromboembolism revealed significant localization of 99m Tc-labeled DTPA-bis-c(RGDfK) conjugate in thrombus and minimal nontarget accumulation. Conclusion: Homobivalent DTPA-bis-c(RGDfK) is a promising radiotracer for immunoscintigraphy since good thrombus-to-normal organ contrast could be observed. These properties can be exploited for specific imaging agent in nuclear medicine for arterial or deep vein thrombotic complications.
2-deoxy-2-(18 F)-fluorosorbitol ((18 F)-fluorodeoxysorbitol): A tracer beyond fluorodeoxyglucose production and quality control
Priya Saxena, Srishti Varma, Manish Dixit, Sanjay Gambhir
Department of Nuclear Medicine, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
Objective: There is an urgent need to develop new positron emission tomography (PET) tracers for detecting certain lesions where fluorodeoxyglucose (FDG) is inadequate or fails. (18 F)-fluorodeoxysorbitol (FDS) or 2-deoxy-2-(18 F)-fluorosorbitol is a useful 18 F-labeled PET tracer that has been developed as noninvasive imaging probe for assessing Oncological and Neurological imaging as well as diagnostic tool that identifies and localizes infections. Unlike FDG, the introduction of (18 F)-FDS or 2-deoxy-2-(18 F)-fluorosorbitol for imaging lesion does not utilize glucose transport. Methods: In this study, we describe the automated synthesis of (1818 F)-FDS, a radioactive probe which was obtained by reduction of intermediate FDG using sodium borohydride (NaBH 4 ) as reducing agent. After quenching the reaction, pH was adjusted to 7.4 and mixture was filtered through an alumina-N Sep-Pak cartridge to give the final purified product. Results: The overall uncorrected radiochemical yield was 50% ± 7% with radiochemical purity ≤95%. Conclusion: This new automated procedure allows (18 F)-FDS synthesis with high reproducibility that is essential for future clinical application.
Neon gas target and synthesis system for the production of fluoro-dihydroxyphenylalanine with a 8.4 MeV deuteron beam
Lokendra Singh, Puja PanwarHazari, Swatantra Sharma, Anil K. Mishra
Division of Cyclotron and Radiopharmaceutical Sciences, Institute of Nuclear Medicine and Allied Sciences, DRDO, New Delhi, India
Objective: The radioisotope production program at the INMAS is based on the utilization of a 16.5 MeV PETtrace cyclotron through 16.5 MeV proton beam or 8.4 MeV deuteron beam. A variety of radiopharmaceuticals are produced for PET and other clinical studies. A production system for fluoro-dihydroxyphenylalanine (FDOPA) for PET studies with (18 F)F2 gas was developed at the INMAS for optimum yield by electrophilic reaction. F2 gas production system includes a high pressure Ne-gas target for the production of large amount of ( 18 F)F2 and a system for the synthesis of FDOPA. Methods: Target design considerations 20 Ne (d, a) 18 F is the most common nuclear reaction to produce F2 gas on the basis of 8.4 MeV deuteron beam bombardment on 20 Ne atoms using natural neon gas. The ( 18 F)F2 deuteron target includes an aluminum container with a bore shaped to fit the beam entering the target. The target chamber is isolated from the cyclotron vacuum chamber by two thin foils. Titanium, 25 μm, facing cyclotron vacuum and Havar, 25 μm, facing target gas. Two helium jets between the foils provide the necessary cooling. Four valves are used for filling, emptying, and isolating the target. A pressure transducer continuously monitors target pressure during irradiation. The target was bombarded with 8.4 MeV deuteron beam at different current at 20, 25, 30, 35, and 40 μA. The time of bombardment was kept constant. Results: A number of production runs was performed with different beam currents for a certain constant time and we obtained high and reproducible yields with this target at 30 μA. Trail production runs yielded FDOPA with a radiochemical purity of other than 92%. Conclusion: The present target design provides high yield of [ 18 F2] gas at 30 μA and minimal loss on the inner surface.
| Radiochemistry and Radiopharmacy|| |
Intranasal delivery of 99m Tc-rivastigmine micelles to brain
Swapna Nabar, Swapnil Mohurle 1 , Yogita Pawar, Sutapa Rakshit, S. H. Moghe, C. Rajesh 2 , Tanuja Shet 3 , Sharmila Banerjee, Vandana Patravale 1
Radiaton Medicine Centre, Bhabha Atomic Research Centre, 1 Institute of Chemical Technology, 2 Medical Cycltron Facility, BRIT, Bhabha Atomic Research Centre, Mumbai, 3 Tata Memorial Hospital, Parel, Maharashtra, India
Objective: To design 99m Tc rivastigmine micelles for nose to brain delivery via olfactory pathways. Methods: Rivastigmine micellar nanocarriers were formulated and checked for particle size, polydispersity index (PDI), and drug content. Rivastigmine was radiolabeled with 99m Tc. Radiochemical purity (RCP) of radiolabeled rivastigmine/micelles was checked by paper chromatography. The stability of radiolabeled drug/micelles was checked in simulated nasal fluid (SNF) and with diethylenetriaminepentaacetic acid challenge test. Postintranasal administration, biodistribution studies were done in rats and autoradiography of rat brain was done to study uptake of 99m Tc-rivastigmine micelles in different parts of the brain. Imaging studies were done in rabbits at various time intervals postintranasal administration. Results: Stable rivastigmine micelles with size of around 25 nm were successfully formulated with the PDI of around 0.25 nm. The RCP of 99m Tc-rivastigmine/rivastigmine micelles was ≥96% which was stable up to 24 h (>90%) and were also stable in SNF and when subjected to DTPA challenge test. The percentage uptake in brain postintranasal administration of 99m Tc-rivastigmine micelles was 14% as compared to 2% with radiolabeled rivastigmine solution. Brain localization and autoradiography studies illustrated uptake of 99m Tc-rivastigmine micelles in different parts of the brain. Imaging studies in rabbits showed significantly higher uptake of 99m Tc-rivastigmine micelles in brain as compared with 99m Tc-rivastigmine solution. Conclusion: 99m Tc-rivastigmine micelles were stable and could be used in future for targeting rivastigmine to brain via intranasal route for treating Alzheimer's disease.
Stability evaluation of fractionated MIBI (TCK-50) and MDP (TCK-30) cold kits
Sutapa Rakshit, Ashok R. Chandak, Nawab Singh Baghel, Sharmila Banerjee
Radiopharmacy Section, Radiation Medicine Centre, Parel, Mumbai, Maharashtra, India
Aims and Objectives: Evaluation of in-vitro stability of fractionated MIBI cold kit used for myocardial perfusion imaging and methylene diphosphonate (MDP) cold kit used for bone scintigraphy. Introduction: Cold kits have been used to prepare radiopharmaceuticals to carry out various nuclear medicine diagnostic studies. A single kit that is used for formulation of multiple patient doses often remains unutilized to the full extent. Moreover, more than two vials are required to be formulated in case of less available activity. Fractionation of kits is therefore necessary for logical usage of these kits. Materials and Methods: MDP cold kit (TCK-30) and MIBI cold kit (TCK-50) from BRIT, 99m TcO 4 Na from column generator (BRIT), Universal pH paper, gamma-TLC miniGITA scanner, chemicals (AR/HPLC grade). MDP kit reconstituted with 2.0 ml N 2 purged saline and dispensed into 4 vials (0.5 ml/vial), and MIBI were reconstituted with 1.5 ml sterile saline and fractionated into 3 vials (0.5 ml/vial). Five sets of different conditions were used for reconstitution of MIBI kit: 1 st - 1.5 ml normal saline, 2 nd - 1.5 ml N 2 purged saline, 3 rd - 1.5 ml N 2 purged saline + 120 µg ascorbic acid, 4 th - 1.5 ml N 2 purged saline + 300 µg gentisic acid, and 5 th - 1.5 ml N 2 purged saline with 100 µg (and 150 µg) SnCl 2·2H 2 O per vial. All fractionated vials were stored at −20°C. Vials are labeled with 2 ml of ~30/60 mCi of 99m TcO4− after thawing on 0, 1, 3, 5, 8, and 15 th day. Labeled products were checked for pH, color, and percentage of radiochemical purity (RCP) at 0 and 4 h of labeling. Results: Appearance of fractionated labeled kit at various time intervals was found to be clear and its pH was between 5.5 and 6.5 at different conditions. The percentage RCP was >95% for MDP up to 8 days of storage in N 2 purged saline. The percentage RCP of fractionated MIBI kit was found >95% in normal condition on the day of formulation, up to 2 days of storage in N 2 purged saline and ascorbic acid, up to 5 days for gentisic acid, and up to 15 days of storage in added SnCl 2·2H 2 O.
Design and evaluation of a novel 99m Tc analog of 131 I-meta-iodobenzylguanidine synthesized via 99m Tc(CO) 3 core for neuroendocrine tumor imaging
Soumen Das, Navin Sakhare, Anupam Mathur, Shubhangi Mirapurkar, Madhava B. Mallia 1 , S. S. Sachdev
Radiopharmaceuticals Program, Board of Radiation and Isotope Technology, 1 Radiopharmaceuticals Chemistry Section, Bhabha Atomic Research Centre, Trombay, Mumbai, Maharashtra, India
Objective: 123/131 I-meta-iodobenzylguanidine (mIBG) is a known radiopharmaceutical used for imaging neuroendocrine tumors. Although the radioiodinated tracers have fulfilled the diagnostic needs, the unfavorable features of the iodine radionuclides have kept researchers interested for a 99m Tc-based substitute, due to the latter's ideal characteristics for nuclear imaging. Hence, the present work attempts to synthesize and evaluate a 99m Tc analog of the radioiodinated derivative. Methods: In brief, xylylenediamine was treated with N,N'-di-Boc-S-methylisothiourea in THF to convert the single amine group to guanidine moiety. This was then treated with t-butyl bromoacetate in the presence of triethylamine base under reflux to obtain the di-substituted guanidine intermediate which was treated with trifluoroacetic acid to yield the final product N-(3-(guanidinomethyl)benzyl)iminodiacetic acid. The latter compound was then radiolabeled with freshly prepared [99m Tc(CO) 3] + synthon (synthesized from carbonyl kit) under boiling water condition to yield the desired negatively charged complex. The formation of the final complex was confirmed through radio-HPLC (Rt: 14 min, radiochemical purity >90%). 99m Tc(CO) 3 complex was then evaluated in SK-N-SH neuroblastoma cell line and results obtained were compared with no-carrier-added 125 I-mIBG (nca 125 I-mIBG). Results: The biological efficacy of the synthesized complex in SK-N-SH neuroblastoma cell line revealed reduced uptake in the cells in comparison to nca 125 I-mIBG and uptake was found to be completely nonspecific as desmethylimipramine, which is a known inhibitor of uptake-1 pathway, could not inhibit the tracer uptake. Conclusion: The preliminary cell uptake studies represented reduced specificity in comparison to 125I-mIBG; nevertheless, the synthetic design provided a clue for derivatization of small molecule such as mIBG for 99m Tc labeling.
Development of cold kits of NOTA-UBI (29-41) and initial clinical evaluation of 68 Ga-NOTA-UBI (29-41) for imaging infection
Archana Mukherjee, Jyotsna Bhatt, ArunaKorde, Jaya Shukla 1 , B. R. Mittal 1 , Ashutosh Dash
Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra, 1 Postgraduate Institute of Medical Education and Research, Chandigarh, India
Objective: The present work was aimed at the development of cold kit for easy one-step preparation of positron emission tomography agent for infection imaging. Toward this aim, cold kits of ubiquicidin (UBI 29-41) fragment conjugated with macrocyclic chelator NOTA were prepared and evaluated. Initial clinical evaluation of 68 Ga-NOTA-UBI (29-41) in patients with suspected infection was also carried out. Methods: Single vial kits of NOTA-UBI (29-41) were formulated and evaluated by physiochemical and biological quality control tests. Radiolabeling using 68 Ga elute from two different generators and quality control analysis was carried out. In vitro uptake of 68 Ga-NOTA-UBI (29-41) was studied in Staphylococcus aureus and in vivo distribution was carried out in normal Swiss mice. Initial clinical evaluation in a patient suspected with diabetic foot was done. 148-185 MBq of 68 Ga-NOTA-UBI (29-41) was injected intravenously into the patient. A blood pool image at 20 min postinjection was followed by spot views of the suspected region of infection (target) and a corresponding normal area (nontarget) at 60 min. Results: Cold kits of NOTA-UBI (29-41) conjugate could be successfully formulated containing 50 µg of peptide conjugate in 0.5 M sodium acetate. 68 Ga-NOTA-UBI (29-41) could be prepared using 68 Ga in high radiochemical yields (>95%) with high radiochemical purity (>95%) using cold kits. 68 Ga-NOTA-UBI (29-41) complex showed retention time of 15.2 min in HPLC radiochromatogram. Specific uptake of 68Ga NOTA-UBI (29-41) fragment was observed in S.aureus. 57% ± 19% of the injected dose was cleared via renal route at 1 h p.i and no significant uptake in vital organs of mice was observed. Initial clinical evaluation in patients with diabetic foot infection showed positive infection foci and clearance from vital organs. Conclusion: This is the first report on formulation of a cold kit of NOTA-UBI (29-41) for the preparation of 68 Ga-labeled NOTA-UBI (29-41) for infection imaging. Initial biological evaluation reveals it to be a prospective agent for imaging infection.
Niobium versus silver target in 18 F production with recovered 18 O water
B. K. Sharma, Shrinibas Nayak, Amit Kumar, S. Banerjee
Board of Radiation Isotope Technology, Navi Mumbai, Maharashtra, India
Objective: Long-term effect of using recovered and purified 18 O-water on niobium (Nb) and silver target in the medical cyclotron and comparisons in the maintenance cost, dose received in the handling of the target, and yield of 18 F (EOB). Methods: The recovered 18 O water was purified by distillation method before its use. The Nb and silver targets were irradiated with recovered 18 O water at 25 µA proton beam in 16.5 MeV cyclotron. The performance has been comparatively very satisfactory with Nb target. Using Nb target, more than 1000 batches of Na- 18 F and 100 batches of 18 FDG and others (F-18) radiopharmaceuticals have been produced and supplied to various Nuclear Medicine Centres. Results: The yield of the Nb target (EOB) was found to be 20%-25% more than that of silver. While the Nb target required maintenance after 8000 µAH use, the Ag target required after 1000 µAH. The typical life of Nb target is 10,000 µAH and that of the silver target is 3000 µAH. The induced activation in the Nb target was found to be quite less as compared to silver target due to more inertness of Nb and hence can be maintained after decay for 2 days, but induced activation in the silver target was very high and required more than 2 months of decay before maintenance. Conclusion: Successful use of recovered 18 O-water in the Nb target has multiple advantages, namely, it reduced the maintenance cost, imparted longer life to the target, reduced doses during maintenance and reduced overall operational cost with an improvement in the production efficiency of the Medical Cyclotron Facility of the center.
Pharmacoscintigraphic evaluation of ophthalmic formulation for enhanced ocular-bioavailability
Ankur Kaul, Tanvi Panwar 1 , Kuldeep Singhal 1 , Mita Dutta 2 , A. K. Mishra
Division of Cyclotron and Radiopharmaceutical Sciences, Institute of Nuclear Medicine and Allied Sciences, New Delhi, 1 SBS PGIBSR, Dehradun, Uttarakhand, 2 Institute of Nuclear Medicine and Allied Sciences, New Delhi, India
Objective: Ophthalmic delivery of drugs is restricted due to numerous ocular barriers, namely, high tear fluid turn over and nasolacrimal drainage. Hence, various nanoformulations are being designed to improve corneal retention. The primary objective of this study was to carry out a scintigraphic evaluation of the formulation for the proposed increased retention at the corneal-site. Methods: The ophthalmic preparation was formulated as solid lipid nanoparticles, which were further incorporated into the solution of Eudragit polymer. This in situ gel laden nanoformulation was characterized for their physiochemical characteristics and further for the in vitro studies including ex vivo transcorneal permeation and ocular irritation studies. The previously formulated nanoparticles were subjected to radio tagging with 99m technetium and the labeling conditions were optimized. The radiolabeled nanoparticles were instilled in the eye of rabbit, and the corneal drainage was assessed by gamma scintigraphy postinstillation. Results: The developed nanoparticles were found to be spherical in shape with a mean particle size of 295 nm, which was validated by transmission electron microscopy images. The in vitro stability studies suggested that the ocular formulation remained stable, showed lesser degradation and optimal shelf-life. A significant higher drug transport across the corneal membrane and increased ocular retention time was observed using the developed formulation. Conclusion: The formulation was observed to be stable, nonirritant, and viable for ocular delivery. The study suggested that the developed formulation is a feasible alternative to conventional eye drops due to its ability to augment ocular bioavailability owing to the longer precorneal residence time and capacity to offer a sustained drug release. However, further efficacy studies of drug-loaded formulation in ophthalmic inflammation models have been planned.
Synthesis and biological evaluation of 99m Tc-labeled dopamine derivative in Parkinson's disease model as a single-photon emission computed tomography biomarker
Ambika ParmarJaswal 1,2 , Surbhi Prakash 1,2 , Virendra K. Meena 1,2 , Ankita Pandey 1,2 , Harleen Khurana 1,2 , Baljinder Singh 1,2 , Sarika Sharma 1,2 , Puja P. Hazari 1,2 , Anil K. Mishra 1,2
1 Division of Cyclotron and Radiopharmaceutical Sciences, Institute of Nuclear Medicine and Allied Sciences, DRDO, New Delhi, 2 Department of Nuclear Medicine PGIMER Chandigarh, India
Background/Aim: Dopamine 3,4-dihydroxyphenethylamine is a neurotransmitter, belongs to catecholamine and phenethylamine families of organic chemicals that plays several important roles in the brain and body. Abnormally high dopaminergic transmission is linked to psychosis, schizophrenia, and Parkinson's disease. Thus, synthesis of dopamine-based radioprobes will provide a method for the quantification of the dopaminergic terminals in the brain and evaluated to study the progression of the diseases linked to abnormal dopamine transport. Materials and Methods: The synthesis of diethylenetriaminepentaacetic acid (DTPA)-bis-dopamine featured conjugation of highly active primary amine of 3,4-dihydroxyphenethylamine to DTPA anhydride under inert conditions. The synthesized dopamine derivative was evaluated in vitro for cell binding, cytotoxicity, kinetics in neuronal cell line whereas in vivo evaluation in terms of biodistribution, imaging, and toxicity was performed in normal Balb/c mice and Parkinson's disease Balb/c mice models created using Rotenone. Sterile kit formulation of DTPA-bis-dopamine was also formulated which can be further used for clinical purpose. Results: The pharmacokinetic studies of (99mTc)-labeled DTPA-bis-dopamine in mice models showed high target to background ratio after 30 min of intravenous administration. Stability studies showed that the complex is stable even after 24 h in serum sample. Preclinical findings showed that the synthesized radioprobe follows both hepatobiliary and renal route of clearance and a good visualization of lesions in Parkinson's disease model with a high target to nontarget ratio. Conclusion: The preliminary studies done for 99m Tc DTPA-bis-dopamine depicts that the radiopharmaceutical may be used as a promising probe for brain imaging in condition of Parkinson's disease.
Synthesis and preclinical evaluation of N-acetylcysteine conjugated to macrocyclic system for tumor imaging using PET imaging
Surbhi Prakash, Puja P. Hazari, Ambika Parmar, Virendra K. Meena, Anil K. Mishra
Division of Cyclotron and Radiopharmaceutical Sciences, Institute of Nuclear Medicine and Allied Sciences, DRDO, New Delhi, India
Introduction: Tumor cells are found to have greater metabolism requiring amino acids for angiogenesis, and N-acetylcysteine (NAC) being a precursor of cysteine is transported in tumor cells through LAT1 receptors. High levels of LAT1 receptors are observed in cancer cells which are responsible for transport of amino acids in them. Taking advantage of this, NAC was conjugated to a new macrocyclic system (ATRIDAT) so that it can be used for diagnostic imaging using PET. The chelating agent is so designed to complex with various metal ions with high stability. Material and Methods: High-dilution conditions were used to synthesize the macrocycle from the scaffold of diethyl aminomalonate (after boc protection) and triethylenetetramine. After subjecting to reaction with tert-butyl bromoacetate, the boc group was selectively cleaved using HCl/EAA. Free amine group was then chloroacetylated and conjugated with NAC from the sulfhydryl of thiol group. It was then cleaved with 20% trifluoroacetic acid to obtain free carboxyl group to aid in metal complexation. MTT was performed to check its cytotoxicity in HEK and A549 cell lines. Radiolabeling was optimized with Ga-68 in sodium acetate buffer in pH range 4-5. Results and Discussion: NAC-ATRIDAT was successfully radiolabeled with >70% radiolabeling yield with Ga-68. Compound was found to be nontoxic in HEK cells with IC 50 in mM range. In vivo micro-positron emission tomography (PET) imaging performed in A549 tumor grafted nude mice shows significant uptake at the tumor site showing its promising future in the field of molecular imaging. Conclusions: A new amino acid-based imaging agent has been synthesized for the purpose of low-grade tumor visualization based on LAT1 receptors, which are overexpressed in tumor cells. The in vitro and in vivo preliminary studies showed encouraging results. High stability with metal ions, good radiolabeling yield, and appreciable uptake at the tumor site support its role in future PET applications.
Evaluation of hospital radiopharmacy-based 68 Ga-labeled radiopharmaceutical: 68 Ga-HBEDCC-PSMA-11
Bhakti S. Shetye, Priya Monteiro, MehjabeenPathan, V. Rangarajan
Department of Nuclear Medicine and Molecular Imaging, Tata Memorial Hospital, Mumbai, Maharashtra, India
Objective: Development of 68 Ge/ 68 Ga generator system boosted development of 68-gallium-labeled radiopharmaceuticals. Recent development is use of nonmetallic silica-based adsorbed resin column. Its advantage is eluate with minimal metallic impurities, which improves labeling efficiency of 68-Ga-labeled radiopharmaceuticals. Introduction of 68 Ga-HBED-CC-PSMA ushered a new path in detection and staging of prostate cancer in PET-CT imaging. We performed labeling procedure of 68 Ga-PSMA-11 using eluate of nonmetallic 68 Ge/ 68 Ga generator. Methods: 5 µg of peptide (DKFZ-PSMA-11) in 900 µl of 0.25 M sodium acetate buffer was used for labeling. We performed 175 labeling procedures in a span of 14 months using two generators (n = 105 I st generator, n = 70 II nd generator). Elution was done using 4 ml of 0.05 M HCl. After heating for 5 min at 1000°C, labeled product was passed through C18 cartridge. Impurities were collected in waste vial. Extraction was done using ethanol. pH of waste and product was measured. Radiochemical purity of 68 Ga-PSMA-11 was determined by instant thin-layer chromatography method using silica adsorbed Al stripes and 0.1 M tri-sodium acetate, (1:1) acetonitrile:water as a solvent. Its stability was evaluated after 2 h. Results: pH of product 68 Ga-PSMA-11 was shown as 5.5 and for waste as 4.0. We calculated labeling efficiency of 68 Ga-labeled product using both generators. Using first generator labeling efficiency of 68 Ga-PSMA-11 was 78%. Using second generator labeling efficiency of 68 Ga-PSMA was 79%. Radiochemical purity of labeled product was >98%. The product showed good stability over a period of 2 h as radiochemical purity was above 94%. Conclusion: ITG 68 Ge/ 68 Ga generator system showed high radiochemical yield of 68 Ga-HBED-CC-PSMA-11. We observed consistency in labeling efficiency of both generators. High radiochemical purity and stability of the labeled product ascertained its use as reliable radiopharmaceutical in diagnosis and staging of prostate cancer.
A novel carbon-11-labeled homodimeric theranostic agent-based on tetrahydroacridin-9-yl) ethane-1, 2-diamine (THA) for disorders involving cholinesterases
Virendra K. Meena, Surbhi Prakash, Ankita Pandey, Shubhra Chaturvedi, Anil Kumar Mishra, Puja Panwar Hazari
Division of Cyclotron and Radiopharmaceutical Sciences, Institute of Nuclear Medicine and Allied Sciences, DRDO, New Delhi, India
Aim: Neurodegenerative diseases are resulted by the reduction of cognitive functions and progressive loss of neurons in basal forebrain, cortical, and hippocampal regions of Alzheimer's brain. Here, we are describing the synthesis, pharmacological evaluation, and positron emission tomography (PET) imaging of a novel class of highly selective and potent homodimerictacrine analogs. The homodimerictacrine derivatives were also evaluated for its AchE and BuChE inhibition activities and for its anti-amyloidogenic activity on Ab-42 peptides in vitro and in vivo. Methods: Synthesis of 5-amino-N1,N3-bis(2-(1,2,3,4-tetrahydroacridin-9-ylamino)ethyl)isophthalamideis proceeded in single reaction of N1-(1,2,3,4-tetrahydroacridin-9-yl)ethane-1,2-diamine (1 mmol) with 5-aminoisophthalic acid (1.3 mmol) in DMF as solvent. 5-amino-N1,N3-bis(2-(1,2,3,4-tetrahydroacridin-9-ylamino)ethyl)isophthalamide was radiolabeled in ethanol via cyclotron radiochemistry. PET imaging was done in brain individually by radiolabeled molecule within 30 min of injection in rat models for neurodegenerative disorders involving cholinesterases. The novel derivative was also checked for its AChE and BChE inhibition activities and for its anti-amyloidogenic activity on Ab-40 peptides in vitro and in vivo on different cell line models. Results: The agent prepared was fully characterized by 1 H nuclear magnetic resonance (NMR), 1 C NMR and mass spectroscopic techniques. Radiolabeling of the ligand with 11 C was done with (>95%) efficiency. Inhibition studies of agent on AchE activity shows a very high IC 50 of 56 nM ± 0.028 and high selectivity toward AchE of 985, from the kinetic inhibition studies suggest the mixed kind of inhibition. Conclusion: The synthesized ligand showed good uptake in brain regions with high cholinesterases expression in PET imaging and showed amyloid aggregation disrupting potency as well. Hence, it could be a promising ligand for neurodegenerative disorder involving cholinesterases.
Automatic dose dispenser: Initial experience
Navratna Kumar Singh, Dhananjay Kumar Singh, Satyawati Deswal, Shashwat Verma, Rahul Kumar, Devesh Chandra Bhatt, Sandeep Kumar
Department of Nuclear Medicine, Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, Uttar Predesh, India
Introduction: Recently, many centers around the world have started using Autodispenser system to reduce the radiation exposure of person working in nuclear medicine. In addition, it is important to maintain the standard for hot lab procedures to optimize the patient care and minimize radiation exposure to all nuclear medicine personnel, patients, and public. Autodispensor is used to dispense and dilute the radiopharmaceutical automatically leading to a high dispensing accuracy and with optimum radiation protection. Aim: The aim of this study was to know the effectiveness in reducing the overall radiation exposure. Materials and Methods: In this study, four persons were involved and using the same radiopharmaceutical ( 99m Tc-methylene diphosphonate) and they injected the same number of patients (10/person) with the same injected dose (20 mCi/patient). The data before using autodispenser were placed in Group 1 while data after using autodispensor were placed in Group 2. The actual injected radioisotope dose of each patient was measured and the dispensing deviation was calculated. Results: Positive result found, it is very much useful in significant dose reduction with high dispensing accuracy in minimum time duration. Conclusion: Efficient for the use in Hot Lab to dispense and dilute the radiopharmaceutical automatically leading to a high dispensing accuracy and with optimum radiation protection.
Preparation and comparative evaluation of 99m Tc-HYNIC-c(KCNGRC) and 99m Tc-HYNIC-PEG2-c(KCNGRC) as angiogenesis imaging agents
Kusum Vats, Drishty Satpati, Haladhar Dev Sarma 1 , Sharmila Banerjee 2
Radiopharmaceuticals Division, Bhabha Atomic Research Center, 1 Radiation Biology and Health Sciences Division, Bhabha Atomic Research Center, 2 Radiation Medicine Center, Bhabha Atomic Research Center, Mumbai, Maharashtra, India
Introduction: Asparagine-glycine-arginine (NGR) peptides bind specifically to CD13 receptors overexpressed on angiogenic tumor vasculature. In the present study, two NGR peptide analogs, HYNIC-c(KCNGRC) and HYNIC-PEG2-c(KCNGRC), were prepared and radiolabeled with 99m Tc as angiogenesis markers for targeted imaging of CD13 receptors. Methods: The peptide conjugates, HYNIC-c(KCNGRC) and HYNIC-PEG2-c(KCNGRC), were manually synthesized by standard Fmoc solid phase synthesis on Novasyn TGR resin. Acetamidomethyl thiol protected cysteines were cyclized on solid support using thallium (III) trifluoroacetate and cleavage of the peptide chain from the resin was carried out using trifluoroacetic acid/ethanedithiol/triisopropylsilane/water (94:2.5:2.5:1 v/v). The peptide conjugates were purified using semipreparative HPLC and radiolabeled with 99m Tc by incubation with ethylenediaminetetraacetic acid, tricine, and stannous chloride (100ͲͺC, 20 min). The biodistribution studies of both the radiotracers, 99m Tc-HYNIC-c(KCNGRC), 99m Tc-1 and 99m Tc-HYNIC-PEG2-c(KCNGRC), 99m Tc-2 were carried out in C57BL/6 mice bearing melanoma tumor. Results: 99m Tc-1 and 99m Tc-2 (>95% RCY) were observed to be stable in vitro till 24 h postpreparation and logP was found to be −2.33 and −2.81, respectively. Maximum tumor uptake was observed at 30 min p.i. ( 99m Tc-1: 2.18 ͱΎ 0.35% ID/g; 99m Tc-2: 2.55 ͱΎ 0.16% ID/g). Blocking studies at 1 h p.i. resulted in ~30% reduction in the tumor uptake of 99m Tc-1: 1.0 ͱΎ 0.19% ID/g and ~40% reduction of 99m Tc-2: 0.79 ͱΎ 0.14% ID/g. 99m Tc-1 exhibited rapid urinary excretion; however, the clearance of 99m Tc-2 was slow and resulted in increased kidney uptake at 180 min p.i. (10.05 ͱΎ 1.53% ID/g). Conclusion: Detailed evaluation of the two radiotracers in different animal model will form part of future studies.
Development of high-performance liquid chromatography method for quality Control analysis of 131 I-sodium iodide solution using cationic modification of C-18 reverse phase column
Vishwas V. Murhekar, Pramod B. Dodke, D. Padmanabhan, Aruna Korde, M. G. R. Rajan
Radiopharmaceuticals Quality Control, Board of Radiation and Isotope Technology, Navi Mumbai, Maharashtra, India
Aim and Objective: Radioiodines ( 131 I-, 124 I-, and 125 I-) are integral part of radiopharmaceuticals. Iodate (IO3− ) is a radiochemical impurity which can be present in radioactive sodium iodide (NaI) solution. Radiochemical purity (RCP) of 131I NaI (specified limit >95%) is performed by paper chromatography using 70% MeOH as mobile phase. Instrument-based methods such as high-performance liquid chromatography (HPLC) are preferred over conventional methods due to their resolution, reproducibility, and accuracy. Many radiopharmaceuticals are now routinely analyzed by HPLC. Here, we describe HPLC analysis using cationic modification of C-18 reverse phase column to separate I-from IO3− for determination of RCP of 131 I NaI solution. Materials and Methods: HPLC parameters: C-18 reverse phase column (5 u, 4.6 mm × 250 mm); mobile phase isocratic with 0.65% (v/v) n-octylamine (modifier) in 0.6% saline pH 7; contains 5% acetonitrile. Flow rate 1 ml/min; elution profile monitoring at 220 nm and NaI (Tl) radiation detector. Potassium iodide (0.1 mg/ml) and potassium iodate (0.2 mg/ml) were used as cold standards. Concentration of modifier and polarity of mobile phase were standardized. Cold standards were added to 131I NaI solution as carriers. The results of RCP were compared with that obtained by standard method. Results: Substantial difference in radiotherapy treatment was observed with I-at 12.19 (±0.19, n = 6) min and IO3− at 3.94 (±0.1, n = 6) min. This difference was favorably exploited for determination of RCP of 131 I-sodium Iodide solution. RCP (98.71%) obtained with HPLC procedure was found to correlate with that obtained by standard method. Conclusion: We successfully demonstrate the utility of ion interaction HPLC for the analysis of 131 I-NaI solution. This method has potential to be applied in regular quality control analysis for determination of RCP of 131 I-NaI solution. Further work on the method is in progress.
Labeling efficiency of commonly used radiopharmaceuticals with thin-layer chromatography: A regular observation in a hospital radiopharmacy
R. Gopinath, S. Srikanth, G. Agnes, P. Madhusudhanan, H. Dhanapathi, Nandini Pandit
Department of Nuclear Medicine, Superspeciality Block, JIPMER, Puducherry, India
Objective: To determine the labeling efficiency of commonly used radiopharmaceutical with thin-layer chromatography. Methods: It is essential to determine labeling efficiency of radiopharmaceuticals before administering to patient. Radiopharmaceuticals prepared in our department were checked for labeling efficiency before administering to patients as it is very important for image resolution and for reducing the radiation exposure to the patient. This can be determined using thin-layer chromatography technique. Each radiopharmaceutical was taken in 1 ml (100 µCi) in a syringe. Required solvents were taken in test tube, to fill the test tube with enough volume to dip the bottom end of Whatmann paper no. 3 of size 1 cm × 8 cm. A small drop of radiopharmaceutical was kept at 1 cm from one end of the paper. Then, they were kept in a test tube vertically which was fixed in a stand and left under observation without handling till the solvent front reached the line 1 cm below another end. The paper was dried and cut into two halves. The halves were counted in well counter. Radiochemical impurity for Tc-99m pharmaceuticals is determined by free 99m Tc and reduced hydrolyzed 99m Tc fractions on total labeled 99m Tc. Labeling efficiency is determined by percentage of labeled 99m Tc in total 99m Tc present in all 3 forms. It is measured by retention factor. The percentage of labeled 99m Tc = 100 − (free 99m Tc + reduced hydrolyzed 99m Tc). Results: Labeling efficiency of different radiopharmaceuticals percentage of 99m Tc methylene diphosphonate (MDP) = 89 + 5.3, 99m Tc methylene diphosphonate = 95 + 4.1, 99m Tc EC = 95 + 3.3, 99m Tc SC = 95 + 4.9, 99m Tc methoxy isobutyl isonitrile = 94 + 5.4, 99m Tc dimercaptosuccinic acid = 89 + 6 and 99m Tc ethyl cysteinate dimer value = 96.7 + 2. Conclusion: TLC method is simple and cost-effective for determining the labeling efficiency of radiopharmaceutical which can be used daily. A slightly higher reduced hydrolyzed 99m Tc is noted in 99m Tc MDP primarily due to the saline component.
Operational and clinical evaluation of (Mo-99)/[Tc-99m]-TCM-autosolex generator at hospital radiopharmacy center
Arpit Mitra 1 , Ashok Chandak 1 , Sangita Lad 1 , Trupti Upadhye 1 , Sharmila Banerjee 1,2 , Sankha Chattopadhyay 2 , M. G. R. Rajan 1
1 Medical Cyclotron Facility, Radiation Medicine Centre, BRIT/BARC, Mumbai, Maharashtra, 2 Radiopharmaceutical Laboratory, Regional Centre, BRIT, VECC, Kolkata, West Bengal, India
Objective: Shortage of high specific activity (HSA) Mo-99 used in producing Mo-99/Tc-99m alumina column generator for obtaining clinical grade sodium pertechnetate (Tc-99m) provided the necessary impetus to develop a closed, shelf-shielded, computer-interfaced autosolex generator for producing Tc-99m from low specific activity (LSA) Mo-99-based methyl ethyl ketone (MEK) solvent extraction technology. This study is aimed to evaluate the operational and clinical efficacy of autosolex generator at hospital radiopharmacy center. The evaluation is carried out by labeling different TCKs (cold kit of Tc-99m radiopharmaceutical) with Tc-99m and subsequently using the agents in routine scintigraphic imaging. Methods: Separation is based on difference in relative conductivity of two phases while MEK solvent extraction technology is used. Labeling, quality control, and scintigraphic imaging were performed as per standard procedures. Results: Operational efficacy was evaluated by extracting Tc-99m from autosolex using three different batch size of LSA Mo-99 (200 [n = 7], 500 [n = 16], and 750 mCi [n = 3]) with extraction yield of 80% ± 5% (n = 96). All batches radiochemical purity (RCP) >98%, pH: 6.5, Mo-99 breakthrough <0.010%, Mo and Al concentration <10 µg/ml, and MEK levels <0.1%. All batches complies sterility and EL <5 EU/ml. All extracted Tc-99m batches labeled with Hynic-Toc, HSA-NC, methoxy isobutyl isonitrile, ubiquicidin, TRODAT along with other TCKs. RCP for all these Tc-99m-labeled radiopharmaceuticals (Tc-99m-Rps) were >95% (n = 146) except >90% for Tc-99m-TRODAT. All these labeled Tc-99m-Rps used for routine scintigraphic imaging in 355 patients. Good signal to noise ratio with proper clearance observed in all patients. Conclusion: Clinical grade Tc-99m could be successfully sourced from autosolex and be efficiently used in labeling of various TCKs. Clinically interpretable scintigraphic images obtained with Tc-99m-Rps prove the operational and clinical efficacy of Tc-99m from the generator for use in hospital radiopharmacy settings.
Development, safety, and gamma scintigraphy evaluation of controlled release nalbuphine nasal drop: An ameliorative approach for instant pain management in traumatic conditions
Kushagra Khanna, Braj Gaurav Sharma, Suresh K. Joshi, Vipin Kumar, Dhruv K. Nishad, Aseem Bhatnagar
Department of Nuclear Medicine, INMAS-DRDO, Timarpur, New Delhi, India
Objective: Nalbuphine is a strong analgesic with a little side effect and dependence profile in animals and man. Nalbuphine is well-recognized agonist/antagonist analgesics from others in having greater antagonist activity and less behavioral effects at analgesic doses than buprenorphine pentazocine and butorphanol. The objective of contemporary study was to develop a novel nalbuphine nasal drop formulation, evaluate and characterize it using several sets of analytical methods including gamma scintigraphy. The toxicity nalbuphine through nasal route was also determined in animals and was found toxic at higher doses. Methods: Nalbuphine was successfully radiolabeled with 99m Tc-pertechnetate using stannous chloride as a reducing agent and found stable up to 24 h in normal saline and serum. Radiolabeled formulation was evaluated in 6 albino Wistar rats for its biodistribution and pharmacokinetic studies by gamma scintigraphy in static manner up to 6 h for its retention in brain and other body organs. Similar set of study was conducted in 12 healthy human volunteers to obtaine similar objectives. Results: Scintigraphy images of healthy human volunteer showed retention of optimized formulations in brain up to 5 h. There was no activity was seen in the stomach by that time within 30 min, 50% of activity was found still in the nasal cavity/nasopharynx. In the parenteral administration of standard doses, it is approximately equipotent in producing analgesia to that of morphine on a weight basis. Significant results obtained through study provide important insight to develop controlled release fast-acting nasal drops of nalbuphine for the management of sever/traumatic pain.
Radiation Medicine Center experience on the preparation of patient doses of 177 Lu-DOTA-TATE: Effect of variation in 177 Lu and peptide ratios
H. Shimpi Hemant, A. Sonwane Geetanjali, Chandak Ashok, A. Lad Sangeeta, J. Nabar Swapna, Banerjee Sharmila
Radiation Medicine Centre, Bhabha Atomic Research Centre, Annexe Tata Memorial Hospital, Parel, Mumbai, Maharashtra, India
Introduction: 177 Lu-DOTA-TATE, a receptor-specific radiotherapeutic agent, is being prepared with adequately high specific activity as in required for peptide receptor radionuclide therapy. It is reported that endocytotic mechanisms that affect the cellular internalization of peptides and may become desensitized at high peptide concentrations which results in lower uptake of radioactivity into target tissues. It is, therefore, desirable to have high specific activity resulting from minimum amount of peptide used in the radiosynthesis protocol. Objective: To study the effect of the variable molar ratios of DOTA-TATE to Lu for preparation of patient doses of 177 Lu-DOTA-TATE. Methods: More than 1000 NETs and other patients have been treated at Radiation Medicine Centre in the last 3 years using in-house synthesized 177 Lu-DOTA-TATE. The optimization of the labeling protocol for preparation with high radiochemical purity using minimum amount of DOTA-TATE is essential in the hospital radiopharmacy. Almost 200 batches of 177 Lu-DOTA-TATE were prepared, in which some of the batches were prepared using lower molar ratios of DOTA-TATE:Lu. Out of 200 batches, 57 batches were synthesized for patients using variable molar ratios of the DOTA-TATE:Lu ranging from 1.5 to 2.5:1. The effect of lower ratios of DOTA-TATE:Lu on radiochemical purity and radiochemical yield was studied. Results: All the batches of 177 Lu-DOTA-TATE were successfully synthesized with very good radiochemical purity and radiochemical yield using 650-3200 mCi 177 LuCl 3 activities and specific activities ranging between 12.7 and 27.5 mCi/µg with the molar ratios of DOTA-TATE:Lu 2.5:1.0. Conclusion: Variable molar ratios of DOTA-TATE:Lu for radiosynthesis did not affect radiochemical purity and radiochemical yield (96%-99%). The direct significance of using lower molar ratio of peptide to Lu results in better efficacies with respect to uptake in lesions of NETs and direct cost-benefit as lower amount of DOTA-TATE is being used.
Development of nalbuphine pressurized metered-dose inhaler and its characterization through gamma scintigraphy in human subjects: An approach for instant pain management in traumatic conditions
Harish Singh Rawat, Kushagra Khanna, Braj Gaurav Sharma, Rajanish Sharma and Aseem Bhatnagar
Department of Nuclear Medicine, INMAS-DRDO, Timarpur, New Delhi, India
Aim: Nalbuphine is well-recognized agonist/antagonist analgesics from others in having greater antagonist activity and less behavioral effects at analgesic doses than buprenorphine pentazocine and butorphanol. Pressurized metered-dose inhaler (pMDI) is an effective choice to deliver drug in the anterior lobe of lungs from where drug can distribute fast and obtain maximum plasma level and reach to the pain suppress receptors. The objective of the contemporary study was to develop a novel nalbuphine pMDI and characterization using gamma scintigraphy in healthy human volunteers. The toxicity of Nalbuphine pMDI was also determined and found safe at 1X and toxic at higher doses, i.e., 4X. Methods: Nalbuphine was successfully radiolabeled and found stable up to 24 h in normal saline and serum as confirmed by instant thin-layer chromatography-silica gel chromatography. pMDI was prepared by filling 134-hydrofluoroalkane propellant and 99m Tc-nalbuphine in an aluminum canister under sterilized environment. The repairable fraction and aerodynamic particle size distribution of the 99m Tc-nalbuphine was determined using Anderson Cascade Impactor (ACI) and calculated by radiometry. Radiolabeled nalbuphine puff was evaluated in 12 healthy human volunteers by ventilation scintigraphy. Results: Nalbuphine pMDI provided a consistent delivered dose is 22% ± 3.2%. The mass median aerodynamic diameter and geometric standard deviation for an aerodynamic particle size distribution determined with an ACI was 4.71 μ and 1.69, respectively. In vivo uptake of the 99m Tc-nalbuphine was considered in real time and activity in lungs and body as the internalized fraction in terms of milligrams as well as percentage. Conclusion: Scintigraphy data showed significant uptake of radiolabeled nalbuphine in the lungs and brain up to 4 h. Results obtained through study provide important insight to develop instant acting pMDI inhaler of nalbuphine for the management of sever/traumatic pain.
Clinical positron emission tomography using 68 Ga-radiopharmaceuticals: Is expensive radiosynthesis module an absolute necessity?
Sudipta Chakraborty 1 , Rubel Chakravarty 1 , E. Radhakrishnan 2 , K. K. Kamaleshwaran 2 , Ajit Shinto 2 , Ashutosh Dash 1
Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Trombay, Mumbai, Maharashtra, 1 Nuclear Medicine and PET Services, Kovai Medical Centre and Hospital, Coimbatore, Tamil Nadu, India
Objective: The commercially available 68 Ge/ 68 Ga generators are generally used in clinical context in conjunction with automated or semiautomated modules for the syntheses of 68 Ga radiopharmaceuticals, which eventually increases the cost of the generator system significantly for a nuclear medicine center introducing 68 Ga-positron emission tomography (PET). The present study is aimed toward the development of a viable strategy for the formulation of 68 Ga-radiopharmaceuticals without the use of such expensive modules to make 68 Ga-based clinical PET more popular and affordable. Methods: An organic matrix-based commercial 68 Ge/ 68 Ga generator was used for the preparation of clinically relevant doses of four different 68 Ga-based radiopharmaceuticals, namely, 68 Ga-DOTA-NOC, 68 Ga-NODAGA-RGD 2 , 68 Ga-DKFZ-PSMA-11, and 68 Ga-BPAMD without using any synthesis module, automatic, or semiautomatic. The radiolabeling conditions were optimized in a hospital radiopharmacy directly utilizing 68 Ga eluted from the generator. Quality control tests of the radiopharmaceuticals were carried out to assess their suitability for clinical use. The clinical utility of the synthesized radiopharmaceuticals was ascertained by performing PET scans in human patients. Radiation dose received by the personnel involved in the generator elution and radiolabeling, dose dispensing, and administration were monitored regularly. Results: All the four 68 Ga-radiopharmaceuticals mentioned above were synthesized with >95% radiochemical purity and they met all the requirements for clinical administration while directly using 68 Ga eluted from the generator. The clinical efficacy of the radiopharmaceuticals synthesized was established by PET scans in human patients. The performance of the generator remained consistent over the 9-month period and >100 clinical doses of different radiopharmaceuticals were prepared with excellent reproducibility and clinical effectiveness. Routine personal monitoring of the radiation exposure of the working personnel involved in the study did not reveal any significant increase in radiation exposure. Conclusion: The present study revealed that expensive radiosynthesis modules available with commercial 68 Ge/ 68 Ga generators may not be an absolute necessity. The promising results obtained in this study would make 68 Ga-radiopharmacy more practical and cost-effective in clinical context.
An Alternative Approach for Evaluation of Radiochemical Purity of Radiopharmaceutical Using Gamma Camera
Biju K, Sushama Awasare, Nawab Singh Baghel, Sharmila Banerjee
Radiation Medicine Centre (BARC) , Tata Annexe Bldg, Parel, Mumbai - 400 012, Maharastra, India
Email Id:- firstname.lastname@example.org
Introduction: Radiopharmaceuticals prepared, to carry out diagnostic nuclear medicine studies, have been evaluated for their radiochemical purity (RCP) by paper chromatography using gamma ray spectrometer with NaI(Tl) detector for counting purpose. This method is time consuming which provides the impetus to explore fast and user-friendly alternative methods of quality control of radiopharmaceuticals. Aims and Objectives: To study the feasibility of gamma camera as counting system in RCP check of radiopharmaceuticals by paper chromatography method. Materials and Methods: This preliminary study was carried out to check QC of 99mTc- MIBI by paper chromatography method with gamma camera as counting system. Whatman paper no 1 of 20 cm length was used as static phase and 100% Methanol as solvent phase. RP was allowed to run till 15 cm and the paper was dried and sealed with cello tape to avoid contamination. This paper was scanned under gamma camera for 5 min after keeping it in thermocol supporting system to keep it in upright position. Strip was scanned with 256 X 256 matrixes with LEHR collimator with zoom 1.5. Region of interest (ROI) was drawn around the whole strip and RP area to calculate RCP. Further, chromatography paper was cut into 1 cm pieces and counted under gamma camera by putting in a test-tube which was kept with 5 cm gap between individual test tubes. Test tubes with cut strips were also scanned under gamma camera with LEHR collimator in 256 X 256 matrixes with zoom 1. To confirm the validity, each test-tube were counted using traditional gamma ray spectrometer after 2-3 days. Each test tube was counted for 10 sec to get good counting statistics. Total 5 sets of QC procedure of 99mTc-MIBI have been carried out. Result: RCP was calculated as ratio of counts from RP area ROI to total counts. Rf value of 1 obtained by all the three methods. Good correlation was found between all the three methods with correlation coefficient > 0.99 between spectrometer counting method and both gamma camera methods (whole strip and cut pieces strip scan). Conclusion: Gamma camera-based method to check the QC of RP by paper chromatography is reliable alternative method and may be used in nuclear medicine centres not having a spectrometer. The advantage of gamma camera method is that it does not require spectrometer. However, the study is to be repeated for more sets and different types of radiopharmaceuticals.
| Dosimetry and Radiation Safety|| |
Radiation protection in the use of beta emitters for radionuclide therapy
Aruna Kaushik, Raunak, Anupama Datta, Anjani K. Tiwari, Anil K. Mishra
Institute of Nuclear Medicine and Allied Sciences, Timarpur, New Delhi, India
Objective: To determine radiation shielding requirements in handling Lu-177 and compare it with other beta emitters. Methods: Typical and maximal electron ranges were calculated for Lu-177 using data from a freely available database. The thickness of Perspex required to stop 0.5 MeV beta particles was calculated. bremsstrahlung yields were calculated for Lu-177 with lead as the shielding material. Thickness of lead required to reduce the radiation levels below permissible limits for handling 3 Ci of Lu-177 was also calculated. This was compared with the shielding requirements in the use of other beta emitters such as Y-90 and I-131. Results: The thickness of Perspex required to stop 0.5 MeV beta particles of Lu-177 was calculated to be 2.1 mm. The bremsstrahlung dose rate was calculated to be 0.5 mR/h at 1 m. The thickness of lead required to reduce the radiation level to 1 mR/h at the location of handling was calculated to be 4 mm. For high-energy beta emitters such as Y-90, 10 mm perspex is needed to stop beta particles without much bremsstrahlung production. Conclusion: Good laboratory practice and suitable shielding are important during preparation, injection, and storage of beta radioisotopes.
Dosimetric analyses of patients with gastroentero neuroendocrine tumors treated with peptide receptor chemoradionuclide therapy using 177 Lu-DOTA-TATE and radiosensitizer-capecitabine
Parul Thakral, Sugandha Dureja, Vineet Pant, Jyotsna, Sunil Kumar, Ishita Sen
Department of Nuclear Medicine, Fortis Memorial Research Institute, Gurgaon, Haryana, India
Objectives: Peptide receptor radionuclide therapy (PRRT) with 177 Lu-DOTA-TATE is becoming a standard therapy for treating inoperable neuroendocrine tumors (NET's). A radiosensitizing chemotherapeutic drug - capecitabine (CAP), the prodrug of 5-FU, is included in the protocol to further enhance therapeutic efficacy. This study aimed to assess the biodistribution and present reasonable estimates of normal organ doses such as liver, spleen, and kidneys using 177 Lu-DOTA-TATE and CAP. Methods: We enrolled 20 patients (male/female patients, 18/2) with mean age of 52.6 ± 12.8 of gastroentero NETs diagnosed with 68 Ga-DOTA-NOC positron emission tomography-computed tomography, histopathology, and biochemical markers. Patients were instructed for the intake of CAP 600 mg/m 2 BD (to a maximum of 825 mg BD) for 14 days commencing 9 days before PRRT. All patients were infused solution of positively charged amino acids for renal protection. 6.66-7.4 GBq (180-200 mCi) of (177)Lu-DOTA-TATE was infused to each patient over 10-15 min. Each patient underwent a series of 3 whole-body scans at 2, 24, and 96 h. The organs included in dosimetric calculation were kidney, liver, spleen, and NETs. All dosimetric calculations were done using the HERMES software. Results: Physiological uptake of (177)Lu-DOTA-TATE was seen in all patients in kidneys, liver, and spleen. Radiation absorbed doses were calculated as 0.29 ± 0.12 mGy/MBq for kidneys, 0.30 ± 0.18 mGy/MBq for liver, 0.63 ± 0.37 mGy/MBq for spleen, and 3.85 ± 1.74 mGy/MBq for NETs. The average effective dose calculated in all twenty patients was 0.05 ± 0.01 mGy/MBq. Conclusions: The maximum cumulative activity of 177 Lu-DOTA-TATE that can be safely administered to a patient within permissible renal threshold (23 Gy) in our study was found to be 76 GBq (2072 mCi). However, there are considerable interpatient differences in absorbed doses of all organs requiring individualized dosimetry for optimizing tumor dose.
Estimation of whole-body radiation exposure to nuclear medicine personnel during synthesis of 188 Re-labeled radiopharmaceuticals
Jyotsna, Sunil Kumar, Suresh Pandey, Renu Sharma, Vineet Pant, Sugandha Dureja, Parul Thakral, Ishita Sen
Department of Nuclear Medicine, Fortis Memorial Research Institute, Gurgaon, Haryana, India
Background: With rapid developments in the field of nuclear medicine therapy, radiation safety of the personnel involved in the synthesis of these radiopharmaceuticals is of prime importance. Rhenium-188 is presently considered to be a versatile radionuclide for various therapeutic applications. It is a generator-produced radionuclide with a utility of both diagnostic and therapeutic agent with aEβ max and gamma energy of 2.11 MeV and 155 keV, respectively. As it is being used to label several pharmaceuticals involving different techniques, it becomes important to monitor the radiation dose received by the radiopharmacist during the synthesis of these 188 Re-radiopharmaceuticals. Aim: The aim of this study was to estimate whole-body radiation exposure to the radiopharmacist involved in labeling of three different 188 Re-labeled compounds, namely, 188 Re-lipiodol, 188 Re-tin colloid, and 188 Re-HEDP. Materials and Methods: The Department of Nuclear Medicine at function magnetic resonance imaging currently synthesizes three different rhenium-188-labeled compounds, namely, 177 Lu-lipiodol, 177 Lu-HEDP, and 177 Lu-tin colloid. A survey meter was used to measure background radiation before start of labeling procedure in the radiopharmacy by keeping it at the spot where the radiopharmacist normally stands during preparation. Data were collected for two synthesis of each 188 Re-lipiodol, 177 Lu-HEDP, and 177 Lu-tin colloid followed by the quality control. The pocket dosimeter was given to the radiopharmacist performing the labeling of 188 Re-labeled compounds which was placed at chest level. All radiopharmaceuticals were synthesized by a single radiopharmacist. Results: Three cardinal principles of radiation safety, i.e., reduce the time, maximize the distance, and use shielding, were applied during the synthesis of Re-188 products. 50 mCi 188 W- 188 Re generator was eluted before the preparation of each radiopharmaceutical. The amount of 188 ReO4− used for labeling with lipiodol, HEDP, and tin colloid was in the range of 120-150 mCi, 90-100 mCi, and 10-20 mCi, respectively. The mean time required to complete the synthesis was 80 min, 41 min, and 130 min, respectively. The mean whole-body radiation exposure was 40.6, 5.7, and 8.2 uSv, respectively. The time required for quality control using instant thin-layer chromatography for all the synthesis was same, i.e., 10 min. The mean radiation exposure during quality control was 3 µSv. The total exposure for all six procedures using 500 mCi was 127 uSv acquired over a period of 3 months. Highest exposure was obtained in the synthesis of 188 Re-lipiodol. Conclusion: Our initial data suggest that the whole-body radiation exposure to the radiopharmacist in radiolabeling and quality control of 188 Re-labeled radiopharmaceuticals is within prescribed limits at the current synthesis frequency keeping radiation safety principles in place.
Unusual artifacts encountered during routine studies on positron emission tomography-computed tomography and gamma camera
Prathamesh Rajai, Natasha Singh, Amit Abhyankar, Purnima Pai, Madhuri Shimpi, Divya Shivdasani
Department of Nuclear Medicine, P. D. Hinduja National Hospital and MRC, Mumbai, Maharashtra, India
Objectives: Unusual artifacts encountered on routine studies on positron emission tomography-computed tomography (PET-CT) and gamma camera studies evaluating cause and precautions. Methods: During PET-CT and gamma camera scans, we encountered three unusual artifacts, which raised concern for possibility of interference in interpretation of scan images. PET-CT artifacts were as follows: (1) multiple equidistant hot spots in linear fashion along length of the patient's body. Multiple horizontal photopenic lines perpendicular to body plane. On probing these hot spots were posterior to scanner bed. In addition to rectifying routine contamination causing issues. PET gantry was examined near which we found cap of cannula. (2) Concentric ring-shaped density changes for which we probed into the gantry and software. (3) Artifact seen in gamma camera image as irregular hot area within FOV seen intermittently during scanning. After ensuring the cause not being contamination, we probed into gamma camera hardware/software. Results: Multiple equidistant hot spots in a linear fashion appear to be caused by cap of cannula located on the PET gantry near protective covering of collimator. This was confirmed on re-acquiring the scan with and without cap at the location where it was found, which reproduced the artifact and rectified image, respectively, and hence suggesting faulty normalization. Thus, ensuring an absolutely free surface with no object over the gantry is worthwhile. The concentric ring artifact seen to be caused by small contrast spillage over CT tube aperture. Proper fitting of mylar window and avoidance of contrast leakage can avoid this occurrence. Irregularly shaped hot spot in gamma camera scan image was visualized due to faulty board (PDOC) within detector of gamma camera and cannot be avoided by users. Conclusion: Few artifacts can be completely avoided with proper precautions, awareness, and routine mandatory checkups while few others may not be under the user's control. On-site problem solving and hence efficient time management while reducing radiation exposure is achievable.
Development of an indigenous kit for the preparation of 99m Tc-macroaggregated albumin for lung perfusion imaging
Archana S. Ghodke, R. Krishnamohan, Jyothi Sharma 1 , Sangeeta H. Joshi, R. Vanaja, S.S.Sachdev
Radiopharmaceutical Programme, Board of Radiation and Isotope Technology, 1 Powder Metallurgy Division, Bhabha Atomic Research Centre, Navi Mumbai, Maharashtra, India
Objective: 99m Tc-macroaggregated albumin (MAA) is used for imaging of the lungs in the diagnosis of pulmonary embolism and other lung diseases. The aim of our work is to develop an indigenous kit for the preparation of 99m Tc-MAA for lung perfusion imaging. At present, this kit is being imported and used. The need to have an indigenous kit for lung imaging was expressed by physicians, and hence the work was undertaken. Methods: A kit formulation was optimized by dissolving 20% high specific activity (HSA) solution, sodium acetate, and sodium chloride in water for injection. pH was adjusted to 6.5 and stannous chloride dihydrate was added. Final pH was adjusted to 5.6, and tween 80 was added and stirred well at 90°C for 10 min. After cooling, 1 ml aliquot was dispensed in vials and lyophilized so that each vial contained 2.5 mg of HSA, 10 mg of sodium acetate, 10.8 mg sodium chloride, 0.1 mg stannous chloride dehydrate, and tween 80. The kits were evaluated for particle size, radiochemical purity, biological efficacy, sterility, and apyrogenicity. Radiolabeling was done by the addition of Na 99m TcO 4 solution to the lyophilized kit vial. Radiochemical purity was assessed by paper chromatography using 85% methanol. Biodistribution was done in Swiss mice at 10 min postinjection. Stability studies were done up to 24 h of the labeled product and up to 6 months after the lyophilization of kit. Results: The radiochemical purity of 99m Tc-MAA was found to be >95% and the percentage of free pertechnetate impurity was less than 10%. The size of the particles was within the range of 10-100 µ and number of particles were approximately 450,000 per kit vial. The biological evaluation showed >80% uptake in lungs, <5% in liver, and <5% in spleen. The kits were stable up to 6 months. Conclusion: The performance of the kit is comparable to that of a commercially available kit.
Development and characterization of melatonin-based UV protectant dermal formulation with higher SPF value: A Gamma scintigraphy evaluation
Suresh K. Joshi, Braj Gaurav sharma, Kushagra Khanna, Vipin Kumar, Dhruv K. Nishad, Aseem Bhatnagar
Department of Nuclear Medicine, INMAS-DRDO, Timarpur, New Delhi, India
Objective: The aim of the present study was to develop an ointment formulation against sunburns caused by ultraviolet-B (UV-B) radiation, predominantly at hilly areas because of high intensity of solar radiation. The developed formulation is shown more effectiveness because it contained higher amount of zinc oxide, which acts as a physical filter/barrier, apart from other ingredients - antioxidants, i.e., melatonin, sea buckthorn oil, carrot seed oil, in specific concentration within the regulatory limits to provide a synergistic effect. Methods: In preliminary experiments, determination of pH, viscosity, spreadability studies were conducted. There are various concentration of ingredients, i.e., zinc oxide, silk gel, N-acetyl cysteine, and curcumin, were tested (F1-F13) and formula F8 was found to be optimum in terms of higher sun protection factor (SPF) value, i.e., SPF-50. Histopathology study in albino Wistar rats (white) was conducted to achieve the toxicological information of developed formulation. In addition, skin irritation, eye irritation study, safety and efficacy studies of sunscreen lotion ware conducted. The whole formulation was radiolabeled with 99m Tc-pertechnetate for its gamma scintigraphy and radiolabeling efficiency found <97.5% confirmed by paper chromatography. Results: Gamma scintigraphy study in twelve human volunteer shown that developed formulation retained on the human forearm skin up to 95% ± 4.5% after 30-min washing period while it was found 85% ± 3.4% with marketed formulation. Final scan of gamma camera suggested significant increased retention of melatonin formulation, i.e., 15% ± 3.15%, which was found ten times higher than 1.5% ± 2.77% of control reading. Conclusion: Outcome of the study concluded that developed dermal formulation may employed against the UV-B radiation and useful against sun burn.
| Endocrinology|| |
Kinetics of 99m Tc-HYNIC TOC uptake in patients with NET
Sutapa Rakshit, Basant L. Malpani, Sandip Basu, Sharmila Banerjee
Radiation Medicine Centre, BARC, Mumbai, Maharashtra, India
Introduction: 99m Tc-labeled octreotide analog, HYNIC-TOC, is a new addition to radio-pharmaceuticals for imaging and screening patients with neural crest tumors. 99m Tc-HYNIC-TOC images are increasingly being used to identify need of 177 Lu-DOTA-NOC/DOTA-TATE therapy in selected patient. Universally, a protocol of whole-body imaging at about 3-4 h postinjection of 99m Tc-HYNIC-TOC is used. Aims and Objectives: This work is aimed to study the time-dependent changes in uptake of 99m Tc-HYNIC-TOC agent in tumors as well as some organs of interest. Materials and Methods: Whole-body sweep scans were acquired in nine patients at about 1, 2.5, and 4 h postinjection of 8-12 mCi of 99m Tc-HYNIC-TOC. Time-normalized and pixel-normalized counts in selected regions such as whole liver (and also selected tumors in liver and apparently normal areas within the same liver), spleen, thyroid, heart, apical region of lungs, and thigh (for muscle uptake) were obtained. Normalized count ratios of liver to heart, liver to spleen, liver to thigh, heart to thigh, and spleen to heart were analyzed for these time points. These data were analyzed to study the pattern of uptake in these sites for at least three time points. Results: All patients selected in the study group had received 177 Lu-DOTA-TATE therapy in one or more sittings and had biopsy-proven NET. On an average, sweep scans were performed at 60, 153 (±23), and 252 (±8) min after 99m Tc-HYNIC-TOC injection. At about 4 h, counts of heart, thigh, and apical lung region and thyroid fell to a range of 64%-76% of that at 1 h, while that in the liver were 101% (±10%) and Spleen were 106% (±9%) of that at 1 h. Within these, gross liver counts changed marginally in 8 out of 9 patients but increased by about 20% in one. However, the tumors in liver showed disparate behaviors as compared to apparently normal areas. It was observed that in about 50% of liver tumors, uptake of 99m Tc-HYNIC-TOC peaked at 2.5 h and reduced subsequently, but in the remaining, the uptake increased up to 4 h of observation. Counts in the spleen were increased by about 10% in three out of nine patients at the end of 4 h. Conclusions: This study highlights the varied uptake patterns of whole liver and tumors within liver with respect to time. It signifies that the metabolic activity within some tumor type is different and may be of use in prognosticating either the success of therapy or the growth kinetics of tumors subtypes.
| Genitourinary System|| |
Comparison of 99m Tc ethylenedicysteine and 99m Tc dimercaptosuccinic acid scintigraphy for the evaluation of renal cortical scarring and differential renal function in patients of urinary tract infection
Vishal Patel, Anitha Lingam, Shwetal Pawar, G. H. Tilve, Mangala Ghorpade
Department of Nuclear Medicine, Seth G. S. Medical College and K.E.M. Hospital, Parel, Mumbai, Maharashtra, India
Objective: In complicated urinary tract infection (UTI), diagnosis of pyelonephritis and subsequent renal cortical scarring is made on Tc-99m dimercaptosuccinic acid (DMSA) scintigraphy. The purpose of the study was to compare Tc-99m EC cortical phase images to that of Tc-99m DMSA for identification of cortical scarring and differential renal function (DRF). Methods: Forty-seven children, mean age of 4.44 years (20 days-10 years) after 6 weeks of active UTI, were included in the prospective study conducted over a period of 2 years. Children with known congenital malpositions and postrenal transplant were excluded. The ethical approval from the local ethics committee and informed consent from parents/guardians were obtained. Tc-99m EC dynamic images were acquired using 128 × 128 matrix size and reframed as 1 min (2-3 min). Tc-99m DMSA static images were acquired using 128 × 128 and 256 × 256 matrix size. The kidney contours were divided in three segments. On visual analysis, photopenic defect >50% area in a segment was defined as large scar and ≤50% of the same was defined as small scar. The Tc-99m EC and Tc-99m DMSA images in 128 × 128 matrix size were compared to identify cortical scars and the same scarred areas were confirmed on 256 × 256 matrix size images of DMSA. Results: There was no significant difference between Tc-99m EC and Tc-99m DMSA in the detection of small or large scars (Cohen's kappa coefficient (κ) −0.94 and 0.9). The sensitivity and specificity of Tc-99m EC for detection of scarring was 98.75% and 99.15%, respectively. The DRF calculated by the Tc-99m EC and Tc-99m DMSA for 94 kidneys shows no statistically significant difference (P = 0.99). Conclusion: Summed Tc-99m EC images provide an acceptable high image contrast to calculate DRF and detect most of the renal cortical scars in normally positioned kidneys. In view of reducing the radiation burden in children, Tc-99m EC cortical phase images can be considered as one of the initial investigations. In patients with inconclusive EC scintigraphy findings only, DMSA scan could be used.
Comparison between 99m Tc-diethylenetriaminepentaacetic acid two sample method, modification of diet for renal disease equation and chronic kidney disease epidemiology collaboration equation based estimated glomerular filtration rate values in Indian donors for renal transplantation
Manish Kumar, Nishikant A. Damle, Geetanjali Arora, Praveen Kumar, Madhavi Tripathi, Chandrashekhar Bal
Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India
Objectives: Glomerular filtration rate (GFR) by plasma sampling technique is considered to be accurate in selection of donors for renal transplantation. Estimate GFR (eGFR) calculations using modification of diet for renal disease (MDRD) equation and chronic kidney disease epidemiology collaboration (CKD-EPI) are simple methods but have not been validated in the Indian population. Hence, we aimed to assess the correlation between these three techniques. Methods: The plasma sampling technique was done using two samples at 60 and 180 min after injection of 1 mCi (37 MBq) 99m Tc-diethylenetriaminepentaacetic acid (DTPA) to 28 healthy donors. Age, sex, height, weight, and plasma creatinine were recorded. Creatinine estimation was done by modified Jaffe's technique. Normalized GFR (nGFR) by two-sample method and eGFR (for MDRD and CKD-EPI) values were calculated using formulas. Results: There were 8 males and 20 females. The mean age was 48.25 years (27-68 years). The mean height was 154.2 cm while mean weight was 55.6 kg. The mean nGFR value was 79.92 for two-sample method while mean eGFR value for MDRD and CKD-EPI were 93.72 and 101.44 ml/min/1.73 m 2 (eligibility value at our institution = 70), respectively. While the correlation between nGFR and eGFR MDRD was poor (correlation coefficient = 0.395), nGFR and eGFR CKD-EPI had a moderate correlation (0.704). Mean total bias between nGFR and eGFR MDRD and CKD-EPI are 13.79 and 21.51, respectively. eGFR MDRD of 68% patients fell within 30% of nGFR (P30) while P30 for eGFR CKD-EPI was 57%. Conclusions: Because of the large variability in eGFR MDRD and CKD-EPI, nGFR estimation using an alternative method like the plasma sampling technique using 99m Tc-DTPA appears necessary while screening healthy donors for renal transplantation.
Comparison between 99m Tc-diethylenetriaminepentaacetic acid two-sample method, Gates' method, and Cockcroft-Gault equation-based estimated glomerular filtration rate values in Indian donors for renal transplantation
Manish Kumar, Nishikant A. Damle, Geetanjali Arora, Praveen Kumar, Madhavi Tripathi, Chandrashekhar Bal
Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India
Objectives: We have compared glomerular filtration rate (GFR) by plasma sampling technique (nGFR) with GFR estimated using Cockcroft-Gault (CG) equation and Gates' method (eGFR) in donors for renal transplantation. Methods: The plasma sampling technique was done using two samples at 60 and 180 min after injection of 1 mCi (37 MBq) 99m Tc-DTPA to 28 healthy donors. Gates' method was done using 5 mCi 99m Tc-DTPA intravenous injection under the gamma camera. Age, sex, height, weight, plasma creatinine, and renal dynamic scan findings were recorded. nGFR and eGFR values were calculated. Data were compared and patients with eGFR falling within 30% of nGFR (P30) were calculated. Results: Eight male and twenty female patients (mean age: 48.25 years; 27-68 years) were included in the study. The mean height was 154.2 cm while mean weight was 55.6 kg. The mean nGFR value was 79.92 while mean eGFR value was 88.73 and 82.61 ml/min/1.73 m 2 by Gates' method and CG equation (eligibility value at our institution = 70), respectively. The correlation between nGFR and eGFR-Gates' was moderate (coefficient = 0.724) and between nGFR and eGFR-CG was poor (coefficient = 0.40). The mean total bias between nGFR and eGFR-gates and between nGFR and eGFR-CG was 8.8 and 2.68, respectively. P30 for Gates' method was 79% and CG equation was 75%. Conclusions: While GFR estimation by Gates' method correlate better with that of plasma sampling technique than CG equation, nGFR estimation using an alternative method like the plasma sampling technique using 99m Tc-DTPA appears necessary while screening healthy donors for renal transplantation.
Evaluating the role of 68 Ga-prostate-specific membrane antigen positron emission tomography-computed tomography for imaging and radiation therapy planning in prostate cancer: Preliminary workup for implementation and technical pitfalls
Atul Gada, Mahitha, Praveen, Sairam, Giri, Nani, Revathy, Dayanithi, Jyotsna Rao, C. Alka, Kalyani, Prashant
Apollo Gleneagles Positron Emission Tomography-Computed Tomography and Cyclotron Centre, Apollo Health City, Hyderabad
Aim: The aim of this study was to evaluate the role of 68 Ga-prostate-specific membrane antigen positron emission tomography-computed tomography (PET-CT) for imaging and radiation therapy (RT) planning in prostate cancer preliminary workup for implementation and technical pitfalls. Materials and Methods: Introduction of Ga-68-PSMA in diagnosis and treatment planning is a novel tool for radiation oncology. After scanning on Biograph 16 PET-CT scanner and validation of localization, volumetric accuracy, and images registration, DICOM images were transferred to radio therapy center. Twenty-five patients were scanned on flat bed with personalized rigid radiotherapy mold covering region of interest to prevent positioning differences. Data were exported to radiotherapy treatment planning contouring system. Target delineations were done using PET-CT. After biological target and critical volume definition, data were sent to treatment planning system of intensity-modulated radiation therapy (IMRT) planning. Using dose-volume histogram dose determined for tumors and critical organs. Plan is exported for IMRT execution to Novalis Tx using eclipse. Using IMRT, different dose prescription can be delivered to multiple target sites with extremely high-dose gradient between tumors and normal tissues in three-dimensional space. Inverse planning is used to calculate optimal shape and intensity of the beam using MLC. Results and Conclusion: Modification in gross tumor volume and planning target volume was demonstrated in various cases. PET offers complimentary information for delineation of primary tumor and corresponding lymph nodes compared to CT and magnetic resonance imaging. Application of biological target volume has direct effect on the chances of cure, on risks, level of side effects and complications. PET-CT makes the treatment more objective and individualized for optimal patient management. Low spatial resolution and high noise in PET images may be a limiting factor for edge detection and contouring. PET information prevented geographical miss in five patients and identified distant metastases in three cases. Ga-68 PSMA PET molecular signature helps radiation oncologist in decision-making with potential to change TNM stage, altering RT treatment regimen and target volumes.
Software comparison for effective renal plasma flow evaluation in renal scintigraphy
Sushama Awasare, K. Biju, Sandip Basu, Nimesh Abhishek 1 , M. K. Ray, M. G. R. Rajan, Nawab Singh Baghel, Sharmila Banerjee
Radiation Medicine Centre (Bhabha Atomic Research Centre), Mumbai, Maharashtra, 1 Amity Institute of Nuclear Science and Technology, Amity University, Noida, Uttar Pradesh, India
Introduction: Renal scintigraphy is commonly used as diagnostic tool to evaluate functional and anatomical information of kidneys by injecting proper radiopharmaceuticals to patients while ensuring minimum radiation dose. Glomerular filtration rate and effective renal plasma flow (ERPF) are two important quantitative parameters to diagnose the status of the kidneys. The efficacy of analysis software is equally important for reliable diagnosis. Aims and Objectives: To compare different software provided by different vendors for ERPF evaluation in renal scintigraphy studies. Materials and Methods: Renogram data of 32 patients were acquired after intravenous administration of 99m Tc-EC for the assessment of ERPF. Patients were referred for ERPF determination for renal toxicity assessment after 177 Lu-DOTA-TATE therapy, which were to be scheduled for next cycle of therapy. The study was acquired on INFINIA dual-head gamma camera single-photon emission computed tomography (SPECT) system for 20 min in 64 × 64 matrix with 1 s/frame in the first phase and 15 s/frame in the second phase. The data were analyzed using modified Gates software (M/s GE Healthcare) available on Infinia system. The data were transferred to E.cam SPECT system using DICOM utility and analyzed using three different software, namely, ITOH (M/s Siemens), ORUICHI (M/s Siemens) Gates software (M/s GE Healthcare). Regression analysis was carried out to note the correlation between the ERPF values obtained using different software. Result: A regression analysis was carried out for modified Gates software provided by M/s GE Healthcare and ORIUCHI, ITOH software provided by M/s Siemens for ERPF assessment. The correlation coefficient (r) between modified Gates and ITOH was observed to be 0.86 (P < 0.001) and correlation coefficient (R) between Modified Gates and ORIUCHI was observed to be 0.85 (P < 0.001). ORIUCHI results were found to be closer to modified Gates software. Further, ERPF values obtained by software provided by M/s Siemens were much lower as compared to software provided by M/s GE Healthcare. Conclusion: It is observed that ERPF values are different using different software. It is, therefore, recommended to use the same software during follow-up studies for renal toxicity assessment. Further, the study may be conducted to derive a multiplication factor among different software from different venders, which will make ERPF assessment software independent so that the studies can be analyzed using any software in subsequent follow-ups.
| Cardiology|| |
Comparative diagnostic accuracy of 99m Tc-sestamibi stress myocardial perfusion single-photon emission computed tomography in men and women in Indian population with coronary angiography as gold standard: A single center experience
Deepa Kumar, Ravinder Singh Sethi, Sandeep Bansal 1 , Padma A. Namgyal, Aditi Khurana Sehgal
Departments of Nuclear Medicine and 1 Cardiology, V.M.M.C. and Safdarjung Hospital, New Delhi, India
Objective: Coronary artery disease contributes to high mortality in women. This study has been done to compare the sensitivity, specificity, and accuracy of 99m Tc-sestamibi myocardial perfusion single-photon emission computed tomography (SPECT) in women and men in the Indian population, considering coronary angiography as the gold standard. Methods: This was a retrospective study. The population for the study included 242 patients, 200 males and 42 females. The patients who had coronary angiography done within 6 months of the stress 99m Tc-sestamibi myocardial perfusion SPECT study were included in the analysis. Patients with documented history of infarction, coronary artery bypass grafting, pathologic Q-waves on the electrocardiogram, left bundle branch block or nonischemic cardiomyopathy were not included. The patients who had any cardiac event between myocardial perfusion imaging-SPECT and coronary angiography were excluded from the study. Two arbitrary cutoff points ≥50% and ≥70% were used for determination of extent of coronary artery disease. Results: The sensitivity, specificity, and accuracy of myocardial perfusion SPECT in women were 79.3%, 63.2%, and 70.6% for 50% coronary stenosis considered as significant stenosis, respectively. The corresponding values for men were 72.6%, 70.8%, and 76.5%, respectively. For 70% stenosis as cutoff, the sensitivity, specificity, and accuracy of myocardial perfusion SPECT in women were 86.8%, 56.8%, and 75.9%, respectively. The corresponding values for men were 86.8%, 60.5%, and 70.5%, respectively. No significant difference was found in sensitivity, specificity, and accuracy between men and women for both 50% and 70% stenosis as cutoff criteria. Conclusion: Stress myocardial perfusion SPECT plays an important role in the diagnosis of ischemic heart disease in women. The sensitivity, specificity, and accuracy are comparable to men. Hence, it is an effective noninvasive method to assess the extent of coronary artery disease in women.
A comparative study to evaluate relation between myocardial supine stress and prone stress imaging
Vipin Yadav, P. K. Pradhan, Deeppankha Datta
Department of Nuclear Medicine, SGPGIMS, Lucknow, Uttar Pradesh, India
Objective: The purpose of this study was to compare the diagnostic value of prone stress imaging with prone (stress) myocardial imaging and attenuation-corrected supine myocardial imaging for the detection of perfusion defect in the myocardial segment. Methods: Thirty consecutive male patients with suspected or known coronary artery disease over a period of 6 months, referred for myocardial perfusion imaging, were recruited in the study. All the patients underwent stress imaging in the supine and prone position with a dual-head gamma camera equipped with and integrated X-ray transmission system (Infinia/Hawkeye; GE Healthcare). The modality of stress was determined based on the exercise capacity and associated comorbidity as left bundle branch block and bronchial asthma, and appropriate stress was performed in the form of either exercise or vasodilator (adenosine or dobutamine). Rest images were acquired in the supine position only whereas poststress images were acquired in both supine (attenuation correction) and prone (NC) position. Results: In this study, we found that the prone stress scan provided some additional information in 2 (06%) patients (1 ischemic defect in inferolateral and 1 in inferoseptal segment). In five (16.7%) patients, the prone images added false information (not proved by the angiogram) in the form of artifacts. These artifacts (n = 8) were as follows: 3 in anterior wall, 2 in anterolateral segment, 2 in inferior wall, and 1 in inferolateral segment of the left ventricular (LV) myocardium. In the supine study, 4 patients (13.3%) had shown false information in the form of artifacts (7 in number), which were as follows: 2 in anterior wall, 1 in septal, 1 in anterolateral, 1 in inferoseptal, and 1 in inferolateral segment of the LV myocardium. Conclusion: It is preferable to do stress prone technique in myocardial perfusion examinations, especially in the absence of single-photon emission computed tomography-computed tomography technology, with similar sensitivity without extra radiation burden to the patients.
| Musculoskeletal System|| |
Role of 99m Tc methylene diphosphonate bone scan in delineation of ischemic zone in cases of severe frostbite: An institutional experience
Arun Ravi John, Anurag Jain, A. G. Pandit, Neeraj Kumar, K. P. Solanki
Department of Nuclear Medicine, Army Hospital Research and Referral, New Delhi, India
Frostbite or cold burn is the medical condition in which localized damage is caused to skin and other tissues due to freezing. Frostbite is most likely to happen in body parts farthest from the heart and those with large exposed areas. At or below 0°C (32°F), blood vessels close to the skin start to constrict, and blood is shunted away from the extremities via the action of glomus bodies. This peripheral vasoconstriction helps preserve core body temperature. In extreme cold, or when certain parts of the body are exposed to cold conditions for long periods, this protective strategy can reduce blood flow in some areas of the body to dangerously low levels. Further to this, crystallization of water in the tissues and subsequent death of tissues occurs in the affected areas. Frostbite is classified into 4° based on the severity of ischemia and the subsequent tissue response. In this case series, we seek to highlight the importance of a 99m technetium methylene diphosphonate bone scan in cases of severe frostbite to precisely delineate the ischemic and reperfusion zones, so as to help the surgeons in carefully deciding if amputation is required and the level of amputation in such cases. This evidence-based approach to the management of severe frostbite cases would lead to decrease in morbidity and improve the quality of life in such patients.
| Brain imaging|| |
Neurodegenerative diseases: A sneak peek with simultaneous positron emission tomography-magnetic resonance imaging
Chandana Nagaraj, Sandhya Mangalore, Arun Kumar Gupta
Department of Neuroimaging and Interventional Radiology, NIMHANS, Bengaluru, Karnataka, India
Objective: To determine the patterns of cerebral glucose metabolism in neurodegenerative diseases. We present a pictorial review emphasizing the advantage of functional cum structural imaging through simultaneous F-18 fludeoxyglucose positron emission tomography-magnetic resonance imaging (F-18 FDG PET-MRI) in the diagnosis of various differential diagnosis of dementia, Parkinson's disease (PD), and clinical Parkinsonism. Materials and Methods: Our study included 12 patients, 9 male and 3 female patients, age ranging from 49 to 73 years posing diagnostic dilemma of subtypes of dementia, clinical Parkinsonism, and PD. All patients underwent simultaneous F-18 FDG PET-MRI scanning of brain 1-h postinjection of 3-5 mCi of F-18 FDG. Patient scans were assessed visually and also using syngo Scenium software. Results: F-18 FDG PET showed characteristic patterns of regional glucose metabolism in patients with idiopathic PD, as well as variant forms of Parkinsonism such as multiple system atrophy, progressive supranuclear palsy, and corticobasal degeneration. In addition, it showed distinct pattern of glucose metabolism in patients with frontotemporal dementia, Alzheimer's disease, and diffuse Lewy body dementia. FDG-PET adds important information that appropriately increased the diagnostic confidence of the subtypes of dementia, PD, and clinical parkinsonism. Conclusion: FDG PET/MRI shows distinct spatial patterns of metabolism in the brain in patients with diagnostic dilemma for different subtypes of neurodegenerative disorders (dementia, clinical Parkinsonism, and PD). Thus, F-18 FDG PET-MRI aid clinicians to make a reasonably accurate and early diagnosis, start appropriate management, also assess response to treatment or predict prognosis.
To establish the normative mean TRODAT-binding ratios in the basal ganglia of cases with normal 99m Tc-TRODAT single-photon emission computed tomography brain scans
Vanshika Gupta, Ritu Verma, Promila Pankaj, Rajeev Ranjan 1
Department of Nuclear Medicine and Positron Emission Tomography-Computed Tomography, Mahajan Imaging Centre, 1 Department of Neurology, Sir Ganga Ram Hospital, New Delhi, India
Objectives: [ 99m Tc]-TRODAT is a potential dopamine transporter imaging agent useful for in vivo assessment of the loss of dopaminergic neurons in Parkinson's and other neurodegenerative diseases. The purpose of our study was to establish the normative mean TRODAT-binding ratios and assess their age-wise distribution in the basal ganglia of cases with visually normal [ 99m Tc]-TRODAT single-photon emission computed tomography (SPECT) scans. Methods: A total of 55 cases who underwent TRODAT SPECT scan in our department during the period of May 2013-September 2016 and were labeled to have visually normal TRODAT scans were included in the study. We calculated specific uptake in the striatum and its subregions, including the putamen and caudate nucleus, by drawing regions of interest over the ipsilateral and contralateral components of basal ganglia, and background was drawn over the occiput. We calculated the ratios of specific striatal binding to nonspecific occipital binding, i.e., binding ratio for the caudate (BR-C), putamen (BR-P), and striatum (BR-Str) as a whole, for each side. The mean BRs were calculated for different age groups. Results: Out of the 55 cases, there were 20 females and 35 males. There were 5 cases below the age of 40 years (males), with mean BR-C, BR-P, and unilateral BR-Str being 0.99, 0.76, and 2.75, respectively. In the age group of 41-50 years (n = 7), the BR-C, BR-P, and BR-Str were 0.77, 0.56, and 2.3, respectively. In 51-60 years (n = 16), BR-C, BR-P, and BR-Str were 0.64, 0.45, and 2.10, respectively. In 61-70 years (n = 17), the BR-C, BR-P, and BR-Str were 0.60, 0.46, and 2.07, respectively. In 71-80 years, the BR-C, BR-P, and BR-Str were 0.54, 0.39, and 1.93, respectively. Conclusion: The age-wise mean TRODAT BRs in cases with normal TRODAT scans shows a declining trend with increasing age of the patient.
99m Technetium [2-[[2-[[[3-(4-chlorophenyl)-8-methyl-8-azabicyclo[3,2,1]oct-2-yl]methyl](2-mercaptoethyl)-amino]ethyl]amino]ethanethiolato(3-)-N2,N2',S2,S2']oxo-[1R-(exo-exo)] in the evaluation of clinically uncertain parkinsonian syndrome
S. T. Arun Raj, Madhavi Tripathi, Satyavrat Verma, Ganesh Kumar, Geetanjali Arora, Vinay Goyal 1 , Chandrasekhar Bal
Departments of Nuclear Medicine and 1 Neurology (CN Centre) AIIMS, New Delhi, India
Objective: Clinical diagnosis of Parkinson's disease (PD) identifies patients who will have pathologically confirmed PD with a sensitivity of 88% and specificity of 68%. The need for a tissue or diagnostic biomarker is thus reinforced. The aim of this study was to evaluate the utility of 99m technetium [2-[[2-[[[3-(4-chlorophenyl)-8-methyl-8-azabicyclo[3,2,1]oct-2-yl]methyl](2-mercaptoethyl)-amino]ethyl]amino]ethanethiolato(3-)-N2,N2',S2,S2']oxo-[1R-(exo-exo)] (Tc-99m TRODAT) SPECT/CT for the diagnosis of presynaptic dopaminergic dysfunction (PSDD) in patients with clinically uncertain parkinsonian syndromes (CUPS). Methods: One-hundred and eighty patients (mean age = 57.4 ± 13.9 years, M:F = 3.3:1) with parkinsonism referred from the movement disorder clinic for Tc-99m TRODAT SPECT/CT (TSCT) were included in this prospective evaluation. Each reconstructed TSCT image was visually evaluated by the nuclear medicine physician and classified as: (1) consistent with PSDD or (2) no definite evidence of PSDD. In case the binding of tracer to the basal ganglia was inadequate for interpretation, the study was either repeated off medication or the patients was called for a F-18 fluoro-dihydroxyphenylalanine (FDOPA) positron emission tomography/computed tomography so that a final classification 1 or 2 could be reached. Results: A total of 175 TSCT were of good quality and could be evaluated. The presence of PSDD on TSCT was concordant with the clinical diagnosis in 90% (159/175), Cohen's kappa was 0.65. In five cases, TRODAT images were inadequate for reporting; in three cases, the study was repeated and found to have PSDD concordant with the clinical diagnosis; and in two cases, FDOPA was done and correctly interpreted. Conclusion: TSCT is a useful diagnostic marker of PSDD that can be used effectively in the diagnosis of patients with CUPS.
| Radionuclide Therapy|| |
Stability and efficacy of a therapeutic dose of Lu-dotatate prepared at a remote-centralized Radiopharmacy: the initial clinical results (work in progress)
Masha Maharaj, Korowlay Nisaar Ahmed 1 , Otto Knoesen 2
Umhlanga Molecular Imaging and Therapy Centre of Excellence, Umhlanga, Durban, Nuclear Medicine, 1 Department of Medical Imaging and Clinical Oncology, Stellenbosch University and Tygerberg Hospital, Cape Town, 2 Technology Division, NTP Radioisotopes Cape Town, South Africa
Background: Lu-177 dotatate therapy has established its role in the management of patients with inoperable or metastasized neuroendocrine tumors. To the best of our knowledge, the clinical stability of Lu-177 dotatate therapy doses prepared at a centralized radiopharmacy and transported to a remote therapy center has never been analyzed or reported. Objectives: To assess the stability in using Lu-177 dotatate prepared from a centralized radiopharmacy and then transported to a remote therapy center. This may create opportunities for remote centers in different countries with no access to onsite production. Methods: The current radiopharmacy, NTP Radioisotopes, is situated in Pelindaba, 634.5 km from the Therapy Centre in Durban. Pelindaba receives the Lu-177 on a Wednesday morning (from ITG in Germany), labels it with dotatate using protocols obtained from two sources in Germany. This process is usually completed by 9 h. The doses are then taken by NTP Logistics to OR Tambo International Airport for clearance for the scheduled flight (1 h) to King Shaka International Airport and it is then taken directly to the practice for administration. We analyzed 19 therapies to determine the stability of the product from preparation to injection. The following were used for analysis: biodistribution of posttherapy imaging versus diagnostic scan lesion uptake, and clinical therapeutic response. Injection, therapy, and imaging protocols were standardized. Results: The mean time from production to injection was 4.93 h (±1.07 standard deviation [SD]). The mode was 4.5 h. The longest time between preparation and injection was 7.33 h. The interim clinical evaluation of six patients who received Lu dotatate therapy: 16% complete response, 33% partial response, 50% SD. Conclusion: Our center experience with Lu dotatate received from a central radiopharmacy suggests that the labeled compound remains stable both in vivo and in vitro with good target delivery and effective clinical outcomes.
Need for repeat therapy in patients with Graves' disease receiving definitive treatment with 5 mCi of radioiodine: A beginners' experience in the Himalayan region
Vandana Kumar Dhingra, Nisha Bhatia 1
Department of Nuclear Medicine, All India Institute of Medical Sciences, Rishikesh, 1 Department of Nuclear Medicine, Cancer Research Institute, Swami Rama Himalayan University, Dehradun, Uttrakhand, India
Objective: Being placed in the hilly state of Uttrakhand with logistic difficulties and patients with cost restraints, radioiodine availability is always a challenge. We aimed to estimate the need for repeat therapy in patients with Graves' disease and Grade 1 goiter with a low dose of (5 mCi) radioiodine. Iodine deficiency leads to increased radioiodine uptake and Uttrakhand is an iodine deficient region. Methods: Patients of Graves' disease with Grade 1 goiter who responded to radioiodine therapy and were on regular follow-up were included in the study. Thyroid gland grading was done by clinical assessment. An average dose of 5 mCi was administered to all patients during the first time. All patients were followed up and were given repeat therapy if they failed to respond with the first dose by 12 weeks. The second dose was administered within 6-8 weeks of failure of first dose and about 7 mCi of radioiodine was given. All patients were followed up for a minimum of 1 year. Results: Thirty-three patients were included in the study. Of these, 7 were males and 26 were females ranging from 18 to 65 years with median age of 45 years. Of the 33 patients, 21 patients responded, i.e., became euthyroid or hypothyroid with the first dose of radioiodine. Twelve patients continued to be hyperthyroid at 12 weeks. These patients were treated with the second dose of radioiodine within 6-8 weeks of failure and showed response in the form of euthyroidism/hypothyroidism after the second dose. Conclusion: Among patients of Graves' disease with Grade 1 goiter treated with 5 mCi of Radioiodine, 63.63% patients responded to one dose of 5 mCi of radioiodine in patients. Almost 36.36% patients required repeat radioiodine therapy with none requiring the third dose. Since the patients belonged to the iodine deficient state of Uttrakhand, we feel that they responded well to lower doses of radioiodine as iodine deficiency may increase iodine uptake.
Keywords: Graves' disease, radioiodine, Uttrakhand
Radionuclide therapy using Re-188 and P-32 patches for treatment of keloids
Priyanka Gupta, Kaushal K. Verma, Rakesh Kumar, Pratik Kumar, C. S. Bal, Arun Malhotra, G. P. Bandopadhyaya
Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India
Objective: To determine the efficacy of radionuclide therapy using Re-188 and P-32 patches for treatment of keloids. Methods: Twenty-four patients with 61 keloid lesions who received radionuclide patch therapy were included in the study. Shape and surface area of the lesions was calculated. Patches conforming to the shape and size of the individual lesions were applied superficially so as to deliver 50 Gy/cm 2 of surface radiation dose. Results: Randomized patients for treatment with P-32 and Re-188 were matched for age, sex, number and extent of lesions into two groups (P > 0.05). Seventeen, 14, and 10 lesions demonstrated a reduction in lesion size of 50%-80%, 80%-99%, and complete disappearance, respectively. There was a >50% decrease in lesion size in 41 (67%) lesions. Sixteen (76%) lesions in P-32 group demonstrated decrease in lesion size of more than 50% as compared to 25 (62%) lesions in Re-188 group, the difference not being statistically significant (P > 0.5). Spectrum of radiation dermatitis ranging from pain itching, erythema, crusting, desquamation, and re-epithelialization was observed as side effects in patients. Conclusion: Radionuclide therapy using Re-188 and P-32 as radioactive skin patches is an effective and safe therapeutic option for the treatment of keloids.
Cost-effective 188 Re-microspheres for selective intra-arterial radionuclide therapy of liver cancer: Initial Results
Jaya Shukla, Naveen Kalra, Madan Parmar, Priya Bhusari, Munish Kumar, Ajay Duseja, B. R. Mittal
Department of Nuclear Medicine, Radiology, Hepatology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
Aims: The selective intra-arterial radionuclide therapy (SIRT) delivers the radiation to the liver cancer via hepatic artery. This therapy minimizes the radiation to normal liver parenchyma and other organs. The treatment is also given prior to surgery and liver transplantation and also postsurgery to reduce the risk of recurrence. The commercially available Y-90 SIRSpheres/TheraSpheres are beyond the reach of most of the patients. In this study, cost-effective, indigenous Re-188 microspheres were formulated for SIRT. Methods: Re-188 microspheres were formulated in house. A clearance from institutional ethics committee and informed written consent from the patients were obtained. The feasibility studies were performed using 74-185 MBq Re-188 microspheres in lipiodol and was delivered via hepatic artery (n = 15). Gamma camera whole-body images were acquired at 1, 6, 12-15, and 24-30 h and single-photon emission computed tomography/computed tomography was acquired 12 h postadministration. For dosimetry studies, urine and blood samples were also collected (n = 3) at various time points. Based on the results of feasibility study, three patients with large tumor and portal vein tumor thrombus were recruited for therapy and dosimetry was performed as described above. Results: Radiolabeling yield and radiochemical purity of Re-188 microspheres was >90% and >98%. Patients showed good and sustained localization of Re-188 microspheres in tumor during the study period. Minimal dose was received by normal liver. However, spleen received ~6% of the ID. Blood and urine showed ~2% ID till 48 h. Significant clinical improvement was observed with no adverse/toxic effects. In two patients >50% reduction in tumor size and in one patient necrosis was noted. Conclusion: The indigenous prepared Re-188 microspheres are easy to formulate in hospital radiopharmacy and are very cost-effective as compared to commercially available Y-90 SIRSpheres/TheraSpheres. Initial treatment data showed very promising results.
| Oncology|| |
Response evaluation to neoadjuvant chemotherapy using 18 F-fluorothymidine interim positron emission tomography/computed tomography in locally advanced breast cancer patients
B. R. Mittal, Jaya Shukla, Gurpreet Singh 1 , Amanjit Bal 2 , Dinesh Kumar, Rakhee Vatsa, Priya Bhusari
Departments of Nuclear Medicine, 1 General Surgery and 2 Histopathology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
Aim: Neoadjuvant chemotherapy (NACT) has been used to downstage the locally advanced breast cancer (LABC) to reduce the chances of recurrence. The functional changes precede anatomic changes, and therefore, functional imaging plays important role in determining chemotherapy response. (F-18)-fluorothymidine (FLT), a structural analog of thymidine, targets upregulated thymidine kinase in salvage pathway for nucleotide synthesis in tumor cells. This study was designed to identify whether F-18-FLT uptake correlates with the final clinical and pathological response. Methods: This prospective study comprised 30 LABC patients (age 28-60 years). All the patients underwent 18 F-FLT positron emission tomography/computed tomography (PET/CT) scans: pretherapy (base line), 7 days post first and after fourth chemo cycles. Surgical samples were used for pathological response. The study was duly approved by the Institutional Ethics Committee and written informed consent was obtained from all the participants. Results: All patients well tolerated NACT. After first chemotherapy, 16 of 30 patients (53.3%) showed partial response (PR) to chemotherapy as decrease in standardized uptake value maximum was ≥30%. In two patients (6.6%), ≥30% increase in standardized uptake value maximum indicated the progression of disease. However, stable disease was noted in 12 patients (40%). At the end of fourth chemo cycle, 4 patients (13.3%) showed complete response (CR), 18 patients (60%) PR, and in 8 patients (26.6%) disease was noted as stable. A patient with CR on PET/CT left after 4 chemo cycles and 1 patient expired before surgery. Out of 27 patients, 3 patients with CR showed no residual tumor in surgical sample, infiltrating ductal carcinoma Grade II was reported in the patients showing PR on 18 F-FLT PET/CT and infiltrating ductal carcinoma Grade III in patients showing stable disease on 18 F-FLT PET/CT after 4 chemo cycles. However, results of 18 F-FLT PET/CT after one cycle have no correlation with pathological response. Conclusion: 18 F-FLT PET/CT after 4 chemo cycles has high prognostic value in response evaluation to NACT in LABC patients
A case of paraneoplastic inflammatory polymyositis with urinary bladder tumor: Role of PET-CT
Pratyusha Bikkina, Swapna Kotha, Zakir Ali
Department of Nuclear Medicine and Positron Emission Tomography-Computed Tomography, Basavatarakam Indo American Cancer Institute, Hyderabad, Telangana, India
Introduction: Patients with idiopathic inflammatory myopathies (IIM) live with an increased risk of developing malignancy compared to the general population. Fludeoxyglucose positron emission tomography-computed tomography (FDG PET/CT) has been increasingly used in the detection and evaluation of occult malignancy responsible for the paraneoplastic syndromes. Case Report: A 50-year-old male was admitted to hospital with complaints of myalgias and progressive difficulty in rising from the chair, walking, and combing hair. Laboratory investigations showed elevated plasma creatine kinase (CK). Magnetic resonance imaging revealed increase in bulk with increased signal intensity on T1-weighted imaging of multiple upper and lower limb muscles. Screening PET-CT showed focal areas of mild diffuse 18 F-FDG tracer uptake in upper and lower limb muscles, in addition to muscle findings, PET/CT showed FDG avid lobulated heterogeneously enhancing mass arising from dome of urinary bladder. Biopsy of the bladder mass revealed small cell cancer. Discussion: The major clinical manifestations of inflammatory myopathies are symmetric and predominantly proximal muscle weakness. Elevations in serum CK, lactate dehydrogenase, aldolase, and aminotransferases occur in most patients. Autoantibodies are found in majority of the patients. Electromyography findings are helpful in confirming the presence of myopathic process and in indicating which muscle groups are most involved. Small cell carcinoma of the urinary bladder is rare malignant tumor of the urinary tract. The disease generally occurs in older males; majority of patients develop painless gross hematuria and few exhibit symptoms of bladder irritation. Histologically, small cell carcinomas of the bladder are identical to small cell carcinomas of the lung. Summary: PET/CT is valuable to identify or exclude an occult malignancy in patients with suspected paraneoplastic syndromes.
Evaluation of 18 F-fludeoxyglucose-positron emission tomography/computed tomography-based volumetric parameters of primary tumor of nonsmall cell lung carcinoma in prediction of disease outcome: Sri Venkateswara Institute of Medical Sciences experience
Manishi L. Narayan, V. S. Krishna Mohan, S. K. Mehabunisa, B. Vijayalashmi Devi 1 , B. V. Subramanium 2 , H. Narendra 3 , T. Kalawat, A. Y. Lakshmi 1
Departments of Nuclear Medicine, 1 Radiology, 2 Radiotherapy and 3 Surgical Oncology, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India
Introduction: 18 F-fludeoxyglucose-positron emission tomography/computed tomography ( 18 F-FDG-PET/CT) has emerged as an essential imaging tool with additional value over conventional imaging for nonsmall cell lung carcinoma (NSCLC). The standardized uptake value (SUV) is a semiquantitative index of metabolic activity and is being increasingly accepted, but there are limitations of SUVmax. Recent studies suggest that 18 F-FDG-PET/CT-based metabolic tumor volume (MTV) and total lesion glycolysis (TLG) can be used as important, independent, and promising prognostic parameters that can be more accurate for prediction of prognosis and disease outcome in NSCLC, compared to SUVmax. Aim and Objectives: This is a retrospective, observational study to evaluate prognostic value of 18 F-FDG-PET/CT-based volumetric parameters, MTV and TLG of primary tumor of NSCLC for prediction of disease outcome and survival at 12 months. Other prognostic markers are age, body weight, AJCC stage, SUVmax, whole-body MTV, and whole-body TLG. Methods: Treatment naive, histopathology proven NSCLC patients with clinical AJCC Stage I to Stage IV aged 18 years and above, of either gender, who underwent 18 FDG-PET/CT scan for initial staging and had follow-up data for at least 12 months or more (>12 months) after 1 st PET scan, referred from oncology services of the Sri Venkateswara Institute of Medical Sciences Tirupati, from January 2013 to December 2014 (24 months) were included for the evaluation. Patients with multiple, synchronous or metachronous malignancies, who died within 1 month after surgery, patients with central nervous system involvement or bulky metastatic disease were excluded. Two methods of data analysis were used for primary tumor MTV and TLG: (i) manual fixed threshold-based tumor segmentation method (at SUVmax of = 2.5 and SUVmax = mediastinal blood pool [MBP] SUVmax) and (ii) relative gradient-based tumor volume segmentation methods (at threshold of 38%, 50% and 60% of SUVmax) were used to define the lesion border. Tumor glycolysis (TLG) of primary tumor was calculated as MTV × SUVmean using the thresholds of SUVmax of = 2.5 and at SUVmax = MBP SUVmax, at 38% SUVmax, 50% SUVmax, and 60% SUVmax. Whole-body MTV and TLG were assessed by drawing isocontour region of interest (ROI) over whole-body including primary tumor, lymph nodes, and metastatic sites with SUVmax threshold of above 2.5 and at SUVmax = MBP. Physiological and benign uptake sites were manually substracted from ROI. Results: Twenty eligible patients were analyzed, including 3 females and 17 males with mean age ± standard deviation, of 60.2 ± 8.6 years and mean follow-up of 12 ± 6.8 months. Clinical stage consisted of Stage II - 2 (10%), Stage III - 11 (55%), and Stage IV - 7 (35%). Out of 20 cases, 10 (50%) patients expired and 10 (50%) were alive at the 12 months of follow-up. When stratified by survival status at 12 months from baseline PET, mean gradient-based pMTV MBP of primary tumor was significantly greater, in those who died (237.43 ml) than in those who survived (104.0 ml) at 12 months. The mean gradient-based pTLG (MBP) was greater (774.68) in those who died than in those who survived at 12 months (602.02). The area under the curve (AUC) for gradient-based pMTV MBP was 0.77 (P < 0.05) in differentiating those who had died at 12 months from those who survived. The cut point of 126.8 (ml) of MTV had a sensitivity of 80%, specificity of 70%, and likelihood ratio (LR) of 2.67. However, the cut point of pTLG MBP of 739.2, had a sensitivity of 80%, specificity of 70%, and LR: 2.67, and AUC was 0.77 (P < 0.05) in differentiating those who had died at 12 months from those who survived. There was no significant difference seen in SUVmax. Of primary tumor between those who survived (12.3 ± 2.6) than those who expired at 12 months (15.1 ± 4). Almost similar, statistically significant results were obtained for whole-body WBMTV and WBTLG with threshold at MBP. Conclusion: PET-based volumetric parameters are potentially better predictor of disease outcome than SUVmax in NSCLC. Our results suggest that primary tumor pMTV measured from threshold-based (SUVmax = 2.5 and SUVmax = MBP) segmentation method was significantly higher in patients who had died at 12 months. Primary tumor and WBMTV was found to be significant factor associated with mortality at 12 months when adjusted for stage and age. ROC and K-M curve analyses indicate that threshold-based TLG may also be a prognostic marker for survival in patients with NSCLC.
Prognostic value of metabolic parameters measured by 18 F-fludeoxyglucose positron emission tomography/computed tomography in surgically resected nonsmall cell lung cancer
Boon Mathew, Nilendu Purandare, Sneha Shah, Archi Agrawal, V. Rangarajan
Department of Nuclear Medicine and Molecular Imaging, Tata Memorial Hospital, Mumbai, Maharashtra, India
Background: TNM stage has been considered the primary prognostic factor in nonsmall cell lung cancer (NSCLC). However, tumor- and patient-specific factors vary even within the same disease stage, creating a heterogeneous population of patients, each with an individual prognosis that requires consideration of patient and tumor-specific factors for the best estimation. Therefore, other prognostic factors besides TNM stages are needed to identify patients at high risk for recurrence, predict prognosis, and recommend individualized adjuvant therapy. Objective: To analyze the metabolic variables, maximum standardized uptake value of tumor (SUVmax) and mean standardized uptake value of tumor (SUVmean) derived from 18 F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) as predictors of overall survival (OS) in operable nonsmall cell lung cancer. Methods: Data of 49 consecutive patients with pathologically proven early-stage NSCLC who underwent preoperative baseline PET/CT were enrolled in the study. The SUVmax as well as the SUVmean was measured using a Philips EBW workstation. The median SUVmax and median SUVmean were used as cutoffs to divide the patient population into two groups. OS was assessed by the Kaplan-Meier method and log-rank test was carried out to evaluate differences between groups. Results: The median follow-up period was 56 months. Of 49 patients, 24 died during follow-up. Median SUVmax and median SUVmean of the primary tumor were 12.7 and 7.1. OS in patients with SUVmax higher than cutoff value of 12.7 was 44 months while 67 months in those with SUVmax less than cutoff (P = 0.033). OS in patients with SUVmean higher than cutoff value of 7.1 was 46 months while 68 months in patients with SUVmean lower than cutoff (P = 0.023). Conclusions: The PET metabolic parameters are significant prognostic factors and a promising tool for better prediction of outcome in patients with operable NSCLC.
Impact of number of lesions analyzed for early response assessment of chemotherapy by 18 F-fludeoxyglucose positron emission tomography/computed tomography using positron emission tomography response criteria in solid tumor in carcinoma lung patients
Swati Rachh, Natasha Singh, Amit Abhyankar, Madhuri Shimpi
Department of Nuclear Medicine, PD Hinduja National Hospital, Mumbai, Maharashtra, India
Objective: The positron emission tomography response criteria in solid tumors (PERCIST) are not specific about the number of lesions that should be analyzed per patient. This study evaluates how the number of lesions analyzed affects early response assessment in carcinoma lung patients undergoing chemotherapy. Methods: In 20 patients with advanced nonsmall cell lung cancer, response after 2-4 cycles of chemotherapy was assessed by the change in standardized uptake value normalized to lean body mass (SULpeak) of the most 18 F-fludeoxyglucose (FDG)-avid lesion (PERCIST_1) and by the change in the sum of SULpeak for up to five lesions (PERCIST_5). The response was also assessed by the change in standardized uptake value normalized to body weight (SUVpeak) of the most 18 F-FDG-avid lesion (PERCIST_1) and by the change in sum of SUVpeak for up to five lesions (PERCIST_5). Results: The response assessment by PERCIST_1 and PERCIST_5 shows concordant results in 18 patients, with 11 patients showing partial metabolic response, 4 patients showing stable metabolic response, and 3 patients showing progressive metabolic disease. The discordant was found in results of two patients with almost perfect agreement in response classification between the two assessments (k = 0.821, P = 0.000). Patients with discordant results were followed up by imaging. There is no difference in response assessed by SUV normalized to body weight as there is no significant change in body weight of the patients in between two positron emission tomography/computed tomography scans. Conclusion: The percentage changes of FDG uptake from baseline to after chemotherapy had a high correlation whether a single hottest lesion or the 5 hottest lesions anywhere in the body were measured. The simple single lesion SULpeak of PERCIST quite accurately reflects behavior of all lesions in the body. For early response assessment, SUVpeak can be used instead of SULpeak.
Utility of 18 F-fludeoxyglucose positron emission tomography/computed tomography in detection of primary site in cancer of unknown primary
V. S. Krishna Mohan, Manishi L. Narayan, Amit Kumar Chowhan 1 , B. V. Subramanian 2 , B. Vijayalakshmi Devi 3 , H. Narendra 4 , Tekchand Kalawat, T. Kannan 5
Departments of Nuclear Medicine and Positron Emission Tomography-Computed Tomography, 1 Pathology, 2 Radiation Oncology, 3 Radiology, 4 Surgical Oncology and 5 Medical Oncology, Sri Venkateswara Institute of Medical Sciences, Tirupati, Andhra Pradesh, India
Introduction: Cancer of unknown primary (CUP) is defined as histologically proven metastatic disease, in which a thorough clinical and diagnostic workup fails to identify the primary site. CUP accounts for 3%-5% of cancer and is the 7 th most frequently occurring cancer in the world and is the 4 th most common cause of cancer-related death in both men and women. 18 F-fludeoxyglucose positron emission tomography-computed tomography ( 18 F-FDG PET/CT) improves detection rate in CUP, facilitates in providing early diagnosis and prompt therapy that are important to increase the survival of these subset of patients. Aims and Objectives: To study the utility of 18 F-FDG PET/CT in Detection of primary tumor sites in patients presented with metastatic disease from unknown primary and to evaluate the clinical impact of this technique on the management of these patients. Methods: All patients with histopathologically proven metastases with no known primary cancer site those satisfying the inclusion criteria referred to the department of Nuclear Medicine from February 2015 to June 2016 for 18 F-FDG PET/CT scan were prospectively studied. Abnormal FDG uptake in suspected site other than physiological sites was reported as possible primary sites. Considering histopathological examination (HPE) and clinical follow-up as gold standard, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 18 F-FDG PET/CT in detection of primary tumor site were calculated. Results: In this study period of 18 months, a total of 64 patients were included, of which 17 lost to follow-up. Remaining 47 eligible cases were analyzed. In 33/47 patients, 18 F-FDG PET/CT scan documented, metabolically active lesion, suspected for primary site and in remaining 14/47, it did not show any suspected primary. In 21/33 patients, histopathology was confirmative for diagnosis (44.6%). In rest 12/33 patients, HPE was suggestive of benign pathology (n = 10) and metastases (n = 2). Sensitivity, specificity, PPV, and NPV for 18 F-FDG PET/CT in detection of primary tumor were 95%, 52%, 65%, and 92%, respectively. 18 F-FDG PET/CT has upstaged the clinical disease in 3 of the 21 true positive cases and it has changed the management strategy in 46.6% of cases. Conclusion: 18 F-FDG-PET/CT is useful, noninvasive screening tool, better than conventional methods, as it offers whole-body evaluation in CUP, especially in cervical and solitary extra cervical CUPs to detect the potential primary site and perform complete staging in a 'one step' procedure at an early stage of diagnostic workup.
| Positron Emission Tomography/Computed Tomography or Single-Photon Emission Computed Tomography/Computed Tomography|| |
Role of fludeoxyglucose positron emission tomography/computed tomography in a suspected case of vascular graft infection
Anurag Jain, A. G. Pandit, Amit Sharma, B. K. Singh
Departments of 1 Nuclear Medicine and Positron Emission Tomography/Computed Tomography and 2 Vascular Surgery, Army Hospital Research and Referral, New Delhi, India
Objective: The study aims to assess the role of fludeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in localization of infectious process in a suspected case of vascular graft infection and correlate the findings with microbiological cultures or with the clinical follow-up. Methods: Twelve patients with suspected graft infection were admitted during the period of January 2011-July 2016. Two patients had undergone endovascular procedure and ten patients had undergone open surgical repair. These were evaluated with complete blood cell count, C-reactive protein, erythrocyte sedimentation rate, and blood culture. Imaging study included CT angiography and FDG PET/CT. Results: Grafts explantation/perigraft collection aspiration and microbiological culture confirm infection with Klebsiella, Pseudomonas, and Escherichia coli. FDG PET/CT shows 100% correlation with microbiologically proven infection. Graft infection is the life-threatening complication after prosthetic vascular reconstruction. The incidence varies from 0.2% to 5%. The clinical presentation is subtle and nonspecific. Conventional imaging cannot confirm the diagnosis at an early stage. At present, the role of FDG PET/CT in suspected vascular graft infection is yet to be defined. Conclusion: 18 F-FDG PET/CT appears promising for precise localization of site of infection and determining the extent of the infection in the graft as well as surrounding soft tissue.
Outlining of body contours in lymphoscintigraphy with scattered photons and 99m Tc point source
Krishnapriya, Pavithradevi, Vianeyabraham, Karunakaran
Department of Nuclear Medicine, SSB, JIPMER, Puducherry, India
Objective: Our objective was to show outlining of body contour with scattered photons and 99m Tc point source. This technique helps in revealing anatomical location of lymph node and also reduces radiation exposure to personnel. Methodology: Lymphoscintigraphy evaluates body lymphatic system in different disease conditions. Lymphoscintigraphic images show only nodes without revealing their anatomical localization. Lymphoscintigraphy using external flood source outlined the body contour, revealed the anatomical location of the node. Thus, using scattered photons and 99m Tc point source, we attempt to outline body contour of the patient. Lymphoscintigraphy was performed with the injection of 0.5 mCi 99m Tc-sulfur colloid in both foot intradermal web spaces. Early, postexercise images were obtained and delayed images after 2 h of injection were obtained in dual energy window setting. It is 130-150 keV for the primary photons and 70-110 keV for the scattered photons. Then, the images were processed for the identification of the diseased lymph node. With point source, static images were taken by moving the point source along the region where effused lymph node present. Results: This study is helpful in identifying anatomical location of lymph node from scattered photons and 99m Tc point source as of using external flood source (transmission imaging). Conclusion: This method of using scattered photon and radioactive marker is useful in identifying anatomical location of lymph node and thus reduces radiation exposure to personnel and avoid additional radiation burden to the patient.
Clinical utility of 68 Ga-NOTA-ubiquicidin (29-41) in assessing different types of infections
Archana Mukherjee, Jyotsna Bhatt, Aruna Korde, Ajit Shinto 1 , K. K. Kamaleshwaran 1 , Indira Upadhya 1 , Ashutosh Dash
Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra, 1 Kovai Medical Center and Hospital Limited, Coimbatore, Tamil Nadu, India
Objective: The purpose of this study was to evaluate utility of 68 Ga-NOTA-ubiquicidin (UBI) (29-41) prepared from an indigenous cold kit in patients with suspected infections. Methods: Cold kit of NOTA-UBI (29-41) was prepared and utilized for the preparation of patient dose of 68 Ga-NOTA-UBI (29-41). Seven patients, with suspected infection, were included in the study. 148-185 MBq of 68 Ga-NOTA-UBI (29-41) was injected intravenously in all the patients. A whole-body positron emission tomography-computed tomography (PET-CT) in 6-7-bed positions were acquired 45-60 min after injection on a Siemens Biograph 6 PET-CT scanner. All patients underwent routine tests for confirming infection within a week after the study. Results: 68 Ga-NOTA-UBI (29-41) could be prepared in >95% radiochemical yield and radiochemical purity using cold kits of NOTA-UBI (29-41). Four scans were positive for infection foci and three showed negative for infection. Negative findings were confirmed to be true negative. Three scans of normal prosthesis, one scan each positive for kidney infection, soft tissue infection in right thigh and for infection in knee joint was obtained. One scan positive for spinal tuberculosis was also obtained. No uptake in vital organs and fast clearance of activity through renal route was observed. Adverse reactions were not observed during image acquisition and within 5 days after the study. A combination of routine tests for infection and 68 Ga-NOTA-UBI (29-41) scans were considered to give maximum confidence toward reporting for the presence of infection. Conclusion: Patient dose of 68 Ga-NOTA-UBI (29-41) was successfully prepared and simple quality control method to check radiolabeling yield was demonstrated at hospital radiopharmacy. 68 Ga-NOTA-UBI (29-41) uptake could clearly delineate infection foci from nontarget normal tissues. Studies reveal 68 Ga-NOTA-UBI (29-41) as a promising agent for prospective imaging of different types of infections.
Clinical evaluation of cold kit formulation developed for preparation of 99m Tc HYNICTATE
Aruna Korde, Ajit Shinto 1 , Archana Mukharjee, Jyotsna Bhatt, K. K. Kamaleshwaran 1 , Indira Upadhya 1 , Ashutosh Dash
Radiopharmaceuticals Division, Bhabha Atomic Research Centre, Trombay, Mumbai, Maharashtra, 1 Kovai Medical Center and Hospital Limited, Coimbatore, Tamil Nadu, India
Objective: The aim of the study was to determine clinical utility of 99m Tc HYNICTATE prepared using indigenously developed kit formulation for diagnostic imaging of tumors over-expressing somatostatin receptors. Methods: The cold kit formulation was evaluated for radiochemical, biological, pharmaceutical purity, and stability. Preclinical animal tumor model studies revealed in vivo receptor specificity of 99m Tc HYNICTATE prepared using developed freeze dried cold kit formulation; hence, further limited clinical studies were carried out in GEP-NETs patients selected for/or undergoing peptide receptor radionuclide therapy (PRRT). 370-555 MBq of 99m Tc-HYNICTATE was injected intravenously in patients and whole-body scanning was carried out, followed by a regional single-photon emission computed tomography/computed tomography (SPECT/CT) of the primary and metastatic sites. The comparative studies were carried with 68 Ga DOTATOC and 99m Tc HYNICTOC. Studies were also carried out in patients undergoing PRRT. Results: 99m Tc-HYNICTATE was prepared by adding 740-2960 MBq of freshly eluted Na 99m TcO 4 in 1-4 mL of sterile saline, directly into the kit vial followed by heating at 100°C for 20 min. The kit formulation was stable for more than 8 months. The radiolabeling yield and radiochemical purity of 99m Tc-HYNICTATE prepared using lyophilized cold kit was consistently >90%. The SPECT images obtained with 99m Tc-HYNICTATE compared well with 68 Ga DOTATOC and 99m Tc HYNICTOC images obtained in same patients for diagnostic imaging. Conclusion: The single vial freeze-dried kit could be successfully used for the preparation of 3-5 patient doses of 99m Tc-HYNICTATE. The diagnostic planar or SPECT/CT images obtained correlated well with other SSTR imaging agents and will be beneficial for patient selection for PRRT and posttherapy evaluation, especially using 177 Lu-DOTATATE.
Potential application of Micro-CT in preclinical research using Animal PET/SPECT/CT system
Ankur Kaul, Puja P. Hazari, P. Ambika P, A. K. Mishra
Division of Cyclotron and Radiopharmaceutical Sciences, Institute of Nuclear Medicine and Allied Sciences, New Delhi, India
Objective: Currently, in biomedical research, there is an increasing trend of utilization of rodents especially mice. Hence, the scaling of clinical imaging techniques to the level of a mouse is actively being pursued. Micro-computed tomography (micro-CT) is considered as one of the emerging imaging techniques for drug discovery and for providing a better understanding of in-vivo pathology, when integrated to a functional imaging modality such as positron emission tomography (PET) or single-photon emission computed tomography (SPECT). Methods: We at INMAS have a tri-modality system: Animal PET/SPECT/CT for in vivo imaging of small animals. The CT images of laboratory animals were coregistered with their respective SPECT/PET scan to pinpoint the targeted site and to improve their image quality. Moreover, micro-CT could also be used to validate an animal model of human disease. The settings of Flex OX ® program were optimized for the different animal species and the calibrations were done. Postacquisition three-dimensional-reconstructed CT data were processed on the Amira® platform. The various murine models studied were of arthritic rats, pulmonary hypoxia models, and tumor grafted nude mice. Results: The micro-CT images of arthritis rat model indicated excessive bone erosion and cartilage matrix damage, compared to the control animal and the (18 F)-NaF PET scans, further validated the CT findings. In the pulmonary hypoxia models, the CT images showed the bilateral patchy lung damage and the coregistered image with (18 F)-fludeoxyglucose PET scan correlated with these observations. The coregistered CT/SPECT image of the [ 99m Tc]-labeled conjugate located the tumor site accurately at 2 h postadministration in the tumor-bearing nude mice. Conclusion: The micro-CT system is not only fast, economical, and noninvasive modality but also gives higher spatial resolution in preclinical research. Further, it can also be an essential tool to evaluate the therapeutic efficacy of nanoparticles in the animal model.
Dynamic 68 Ga-PSMA PET/CT scan-A technical perspective
Chanchala Umesh Kale, Anil Parab, Laxman Khande, Parag Aland, V. R. Lele
Nuclear Medicine and Positron Emission Tomography-Computed Tomography Department, Jaslok Hospital and Research Center, Mumbai, Maharashtra, India
Objective: To assess the utility of dynamic 68 Ga-prostate-specific membrane antigen positron emission tomography-computed tomography ( 68 Ga-PSMA PET-CT) scan. Materials and Methods: Thirty patients with raised prostate-specific antigen (PSA) levels were selected (age 45-81 years). 68 Ga-PSMA, 68 Ga-labeled PSMA was prepared using semiautomatic method. A low-mA CT scan of pelvis region was taken. When patient bed was moved in the PET gantry, 68 Ga-PSMA (2-5 mCi) was injected through intravenous line. PET scan data were acquired in list mode for 5 min. CT parameters: Low-mA, non I V contrast. PET parameters: 68 Ga isotope selected, 5 min list mode, single bed (pelvis region) acquisition. List mode reconstruction parameters: Q clear method: 30 s/view (79 transaxial i mages), 10 views (790 transaxial images). A routine whole-body PET-CT scan was performed 1 h later. Standardized uptake value uptake in prostate gland in initial dynamic and at 1 h whole-body scan were noted and compared. Results: (1) Dynamic images processing reconstruction time was found to be 5-8 min. (2) Urinary Bladder activity was not visualized in any patient in 1 st 5 min of study. (3) Uptake in prostate gland could be easily visualized. There was no background activity. The only additional tracer activity was seen in blood vessels. Uptake in prostate region during dynamic acquisition reached maximum at 30 s to 1 min and it remained almost constant as seen in time activity curve. (4) Significant uptake was also seen in bone metastases, lymph nodes during dynamic images in some patients. Increased uptake in dynamic and scan at 1 h was seen in 28 patients confirming cancer. Increased uptake in the initial image and decreased in 1 h image was found in two patients confirming prostatitis. Normal prostatic tissue did not show uptake at flow or on delayed static images. Conclusion: In prostate cancer patient, urinary bladder activity overlaps the prostate gland in 1 h PET-CT scan image. In this scenario, dynamic 68 Ga PSMA-PET/CT study is useful. Hence, dynamic 68 Ga-PSMA PET-CT scan should be routinely performed.
Role of fludeoxyglucose positron emission tomography/computed tomography in diagnosis of large vessel vasculitis in suspected cases of fever of unknown origin
K. P. Solanki, Anurag Jain, Arun Ravi John, Abhishek Mahto, Abhinav Jaimini
Department of Nuclear Medicine, Army Hospital (R&R), New Delhi, India
Fever of unknown origin (FUO) was defined by Petersdorf and Beeson in 1961 as (1) temperatures of >38.3°C (>101°F) on several occasions; (2) a duration of fever of >3 weeks; and (3) failure to reach a diagnosis despite 1 week of inpatient investigation. While this classification has stood for more than 30 years, Durack and Street have proposed a revised system for classification of FUO that better accounts for nonendemic and emerging diseases, improved diagnostic technologies, and adverse reactions to new therapeutic interventions. This updated classification includes (1) classic FUO, (2) nosocomial FUO, (3) neutropenic FUO, and (4) FUO associated with HIV infection. As we know that 18 F-fluorodeoxyglucose (FDG) uptake is based on the cells' use of glucose as a source of energy, it can be observed in infectious, inflammatory, and tumor-related processes. There is growing body of evidence which demonstrates the role of 18 F-FDG positron emission tomography/computed tomography (PET/CT) in the diagnosis of large vessel vasculitis which is commonly associated in cases of FUO. We report two cases of pyrexia of unknown origin evaluated by FDG-PET/CT and diagnosed as a case of vasculitis.
| Gastroenterology|| |
Correlation of 99m Tc HIDA scintigraphy with magnetic resonance cholangiopancreatography in evaluation of biliary strictures: An initial experience
Shashwat Verma, Satyawati Deswal, Dhananjay Singh
Department of Nuclear Medicine, Dr. Ram Manohar Lohia Institute of Medical Sciences, VibhutiKhand, Lucknow, Uttar Pradesh, India
Objective: The aim of this study was to evaluate the diagnostic accuracy of hepatobiliary scintigraphy (HBS) in detecting biliary strictures. Methods: We retrospectively reviewed data of 14 patients with biliary strictures referred for HBS. Patients' age range was 20 years to 65 years, of which 9 were female and 5 male. All patients had undergone magnetic resonance cholangiopancreatography (MRCP) and 99m Tc-HIDA scan (HBS). The HBS results were categorized as no obstruction or obstruction (partial or complete). The presence of biliary strictures was confirmed by MRCP. Results: Out of 14 patients, 12 patients showed obstruction on HBS. Out of those 12 patients, 10 were positive on MRCP also. In rest of the two patients, MRCP did not reveal any significant abnormality. Among two patients in whom HBS was normal, one patient showed stricture on MRCP and in other, MRCP was also normal. Out of total 14 patients, 5 were kept on medical management and one lost to follow-up. Among the 12 HBS-positive patients, 8 patients were taken for surgical management, i.e., 67% underwent intervention either in the form of stenting or surgery. The sensitivity of HBS was 91%, specificity 33.33%, positive predictive value 83%, and negative predictive value 50%. Conclusion: HBS is useful for evaluating hepatocellular function as well as detecting biliary obstruction. Because of its noninvasiveness and convenience, HBS is commonly used to evaluate the presence of biliary strictures. Considering the relatively good sensitivity and positive predictive value, the presence of biliary obstruction on HIDA scans can be quite reliable and offer a guiding tool for proceeding to the next step (MRCP, endoscopic retrograde cholangiopancreatography or percutaneous transhepatic cholangiography to confirm the presence of biliary strictures). The low specificity and negative predictive value in our study was due to less number of patients. MRCP although being noninvasive and with a higher sensitivity and specificity does not allow therapeutic intervention and also cost-effectiveness is of concern. Hence, HBS can be considered for initial imaging to rule out biliary strictures followed by MRCP where indicated.
Gamma Scintigraphy evaluation of long-acting calcium chloride tablet against gastroesophageal reflux disorder in human subjects: Innovative Management of gastroesophageal reflux disorder
Braj Gaurav Sharma, Harish Rawat, Suresh K. Joshi, Dhruv Kumar Nishad, Mitra Basu, Aseem Bhatnagar
Department of Nuclear Medicine, INMAS-DRDO, Timarpur, New Delhi, India
Objective: Calcium chloride is an essential calcium channel agonist which plays an important role in the contraction of muscles by triggering calcium channel. We hypothesized its role in the treatment of gastroesophageal reflux (GER) and vomiting disorder by contraction of upper gastrointestinal part. The objective of the present study was to develop and accumulate efficacy data through scintigraphy. Methods: Gastroretentive formulation of calcium chloride was prepared by direct compression method. Thirteen tablet formulations were designed with the help of sodium chloride, HPMC-K4M, and carbopol-934 along with effervescing agent sodium bicarbonate and citric acid. In preliminary experiments under in vitro buoyancy, tablet swelling ability and drug dissolution studies were conducted in 0.1 N HCl at 37°C ± 0.5°C. Whole formulation was radiolabeled with 99m Tc pertechnetate for scintigraphy-based in vivo evaluation. Optimized formulation, i.e., F8 found best fitted for Korsmeyer-Peppas equation with an R 2 value of 0.993. 99m Tc-sulfur colloid (300 µCi) was given to subjects, and dynamic images were acquired up to 30 min with frame rate of 30 s/frame as a control scan. Results: Level of reflux was found 2.083 ± 0.76 in GER-positive patients group prior to giving any treatment while it was found to be 1.5±.50 when treated with formulation. The percentage of reflux was 1.917 ± 0.76 in control group while in treatment group it was reduced to 1.250 ± 0.43. Frequency of reflux was noted 2.083 ± 0.86 which was significantly reduced in the treatment group with 1.417 ± 0.49. Duration of reflux was significantly reduced in the treatment group as followed by 1.417 ± 0.49 and 1.167 ± 0.37. Gastric retention (6 h) was evaluated by gamma scintigraphy in healthy human controls which shown its effectiveness in GER-positive population. Conclusion: In summary, the present study results indicate the role of calcium ions-based oral formulation proven as an advance approach for the management of GER disease.
Gamma scintigraphic evaluation of newer approaches for the assessment of gastric emptying time in the human subjects
Braj Gaurav Sharma, Sandeep Soni, Dhruv K. Nishad, Aseem Bhatnagar
Department of Nuclear Medicine, INMAS-DRDO, Timarpur, Delhi, India
Objective: Gamma scintigraphy is the most reliable method to measure gastric emptying time, but there is lacuna in the standard methodology as per the US guidelines. There is a lack of standardization of the test, including differences in meals, patient positioning, frequency, and duration of imaging. A wide range of radiolabeled test meals have been used for gastric emptying scintigraphy since decades. The objective of the present study was to develop the easy, robust, and reliable method for the measurement of gastric emptying time. Methods: Two eggs (white chicken egg) were radiolabeled with 99m Tc-pertechnetate. Reduced 99m Tc-pertechnetate (1.5 µCi in 300 µl saline solution) was injected by 0.18 mm syringe into the raw egg through the egg shell. Tin chloride (SnCl 2 ) was used as reducing agent to optimize the radiolabeling efficiency. Thereafter, radiolabeled egg was vortexed for 30 s for complete distribution of tracer inside egg yolk. The eggs were boiled in the microwave for keeping them for 3-4 min at 100°C. Egg protein which includes the albumin, mucoprotein, and globulins was radiolabeled by 99m Tc-pertechnetate. Radiolabeled egg along with 200 ml of fruit juice was given to the twelve healthy and gastroesophageal reflux-positive human subjects, and scintigraphy images were acquired in static manner 2 min/image with the difference of 30 min up to 4 h by single-photon emission computed tomography-computed tomography gamma camera Siemens. Results: Radiolabeling efficiency of eggs were found >98% ±2 up to 6 h. T half (T1/2) of gastric emptying of healthy controls was found 45 ± 10 min compared with control method 52 ± 14 m. T1/2 of gastroparesis found 90-125 min compared with results came through conventional methodology, i.e., 70-150 min. Conclusion: Gamma scintigraphy study showed usefulness of the current method for the evaluation of gastric emptying in human subjects. Results of the present study have shown some promising results and improve the clinical utility of the GE test.
| Miscellaneous|| |
Semiquantitative scintigraphic assessment of salivary gland function with 99m Tc-pertechnetate uptake in patients undergoing radiotherapy treatment for head and neck cancers
Nisha Bhatia, Vandana K. Dhingra 1
Department of Nuclear Medicine, Cancer Research Institute, Swami Rama Himalayan University, Dehradun, 1 Department of Nuclear Medicine, All India Institute of Medical Sciences, Rishikesh, Uttarakhand, India
Background: Salivary glands, usually irradiated during radiotherapy for head and neck cancers, can lead to impaired salivary gland function. The most common cause of morbidity for such patients is radiation-induced xerostomia. With advent of intensity-modulated radiation therapy, all efforts are made to preserve salivary function. Scintigraphy using 99m Tc can be used for qualitative (images) and graphical assessment (time activity curves) of salivary gland function. Aim: The aim of this study was to assess salivary gland function semiquantitatively by evaluation of salivary gland 99m Tc uptake. Methods: The study included 18 patients (16 males and 2 females) undergoing radiotherapy for head and neck cancers. All patients underwent salivary scintigraphy at baseline; end of radiotherapy, and at 6 months of radiotherapy. 99m Tc uptake was calculated. Other scintigraphic data such as visual analysis and graphical display (time activity curves) also performed. Results: Visual analysis of images revealed impairment of tracer uptake in seven patients postradiation. The excretion response (graphical analysis) to stimulant lemon was totally or partially affected in 16 patients. Mean 99m Tc uptake values and standard deviation for baseline studies was 0.45% ± 0.23%, at the end of radiotherapy was 0.44% ± 0.2%, and after 6 months of completing radiotherapy was 0.38% ± 0.08%. In patients who showed impaired tracer uptake on visual analysis, impaired excretion on graphical result was symptomatic, 99m Tc uptake percentage was also found to fall postradiotherapy. However, if only uptake was taken as a parameter, no statistically significant difference was observed. Conclusion: The study shows that semiquantitative assessment with uptake calculation is an additional parameter which could be helpful in assessing salivary function with more certainty where visual or graphical methods are equivocal. However, standalone 99m Tc uptake percentage values are not of significance in evaluation of salivary gland function.
Determination of percentage of retained postinjection radioactivity of Tc-99m tetrofosmin in syringe set for routine myocardial perfusion imaging scan
Korepupriyanka, Tattwamasi Bharadwaj, Anil Parab, Sunit Mitra, Chanchala Kale, Parag Aland, Vikram Lele
Department of Nuclear Medicine, Jaslok Hospital and Research Centre, Mumbai, Maharashtra, India
Objective: Adequate delivery of accurate dosage of radionuclide is quite essential to achieve reportable quality of images and reducing count-related artifacts. Swanson et al. demonstrated that adhesion of 99m Tc-sestamibi to the injection set was 20.1% ± 8.0% of preinjected activity. To determine the percentage of 99m Tc-tetrofosmin activity retained in dispovan plastic syringe set with rubber plunger, postinjection during myocardial perfusion imaging studies. Materials and Methods: Thirty-three injections (21 low-dose injections 5.28 ± 0.8 mCi and 12 high-dose injection, i.e., 17.4 ± 1.2 mci, in 1.5 mL) performed with dispovan plastic syringe set with rubber plunger were included at the time of abstract submission. However, it is an ongoing study and the expected sample size is a minimum of 120 injections. Pre- and post-injection syringe counts are measured by Veenstra dose calibrator and retained activity (RA) was calculated from decay corrected preinjection activity (DCP) by formula (postinjection activity/DCP) × 100%. Results: Preliminary data suggest that RA in low- and high-dose injections was found to have a minimum and maximum values of 3.4%-14.6% and 4.4%-7.7%, respectively. The percentage of RA in low- and high-dose injections has a mean of 9.8% ± 2.9% (median-9.3%) and 5.2% ± 1.2% (median-5.1%), respectively. Overall, the percentage of RA was found to be 8.1% ± 3.3% (median - 7.6%). Conclusions: Preliminary data suggest that 8.1% ± 3.3% of RA was detected in the syringe set and dilution of the preinjection dose is recommended to nullify the effect of adsorption to the walls of syringe set. However, the final data will be determined after the completion of the study.
To compare the reliability and accuracy of glomerular filtration rate calculated by the diethylenetriaminepentaacetic acid technique versus the ethylenedicysteine technique
Rahul Kumar Tripathi
Department of Nuclear Medicine, Dr. RMLIMS, Lucknow, Uttar Pradesh, India
Introduction: Radionuclide evaluation of genitourinary system includes estimates of renal perfusion and function. Tc-99m diethylenetriaminepentaacetic acid (DTPA) is excreted almost exclusively through glomerular filtration and hence used for the evaluation of glomerular filtration rate 2 (GFR 2). About 20% of Tc-99m-DTPA is extracted from the blood with each pass through the kidney 2-3. Less than 10% of injected DTPA is bound to plasma proteins; hence, Tc 99m DTPA tends to underestimate GFR. The images acquired at high creatinine level are of poor quality leading to fallacious results in patients with impaired renal function 6. Tc- 99m ethylenedicysteine (EC) 6, a metabolite of ethylene cysteine dimer (ECD), is a new technetium-labeled renal tubular function tracer introduced as an alternative to ortho-iodohippurate and with imaging qualities similar to 99m Tc-mercaptoacetyltriglycine. Within 1 h, 70% of 99m Tc-EC is excreted in the urine. It is used to measure effective renal plasma flow (ERPF). GFR is 20% of ERPF. Aim: To compare the reliability and accuracy of GFR calculated by the DTPA technique versus the EC technique. Method : The GFR obtained by the EC technique is compared with the GFR obtained by the DTPA technique, and both are compared with the "gold standard" technique of 24-h urine creatinine clearance. Result : The GFR estimated with 99m Tc-EC correlated better with GFR measured by 24-h urine creatinine clearance. The GFR measured with 99m Tc-DTPA was statistically different from that measured with 24-h urine creatinine clearance but in some cases both (EC and DTPA) gave nearly same results. Conclusion: The GFR estimated with 99m Tc-EC is comparable with that measured with 24-h urine creatinine clearance while the GFR values measured with 99m Tc-DTPA presents a significant statistical difference from that measured with 24-h urine creatinine clearance.
Comparative evaluation of 24-H 131 I thyroid uptake by gamma camera using high-energy collimator with standard probe-based method
Devesh Chandra Bhatt, Satyawati Deswal, Dhananjay Kumar Singh, Shashwat Verma, Rahul Kumar, Navaratna Kumar, Sandeep Kumar
Department of Nuclear Medicine, Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
Objective: To make a quantitative comparison between 24-h thyroid uptake calculated by thyroid uptake probe and under gamma camera and after administration of a diagnostic 131 I dose in patients with benign thyroid disorders. Methods: Informed consent was taken from all the patients. This study group comprised 20 patients, of which 8 were males and 12 females (age range 25-50 years). These patients had benign thyroid disorders and were referred for thyroid evaluation to our department. A liquid form of 131 I (50 µCi [1.85 MBq]) was administered to patients with adequate flushing of vial to ensure maximum oral administration of dose. The dose was prepared with the help of pipetting technique and preadministration counts were taken with activity places inside Lucite neck phantom. A 24-h 131 I uptake was measured with the help of thyroid probe and also under gamma camera with patient lying supine and detector at a distance of 25 cm from the neck anteriorly. Pre- and post-131-I administration counts were taken under gamma camera. Results and Discussion: In 19 patients of 20 patients, the radioiodine uptake value measured by gamma camera was around 50% of that measured by thyroid uptake probe. Therefore, by applying a correction factor, we can equate the uptake value of probe method and gamma camera method. Conclusion: On the basis of precision in counting by thyroid uptake probe, it takes the edge over gamma camera method. Therefore, gamma camera method can never be an ideal substitute. Hence, thyroid uptake probe method cannot be replaced by gamma camera method.
Modern routine for nuclear medicine technologists for the determination of exact timing for adding single-photon emission computed tomography/computed tomography to a whole-body bone scan
Sandeep Kumar, Satyawati Deswal, Dhananjay Kumar Singh, Shashwat Verma, Rahul Kumar, Navratna Kumar, Devesh Chandra Bhatt
Department of Nuclear Medicine, Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
Introduction: In Nuclear Medicine Department, bone scintigraphy is performed frequently to identify skeletal metastatic lesion. Maximum patients with skeletal pain show abnormal uptake in bone scintigraphy. In whole-body scintigraphy, we acquired an anterior and posterior projection image. Aim: The objective of the present study was to access the value of additional regional single-photon emission computed tomography/computed tomography (SPECT/CT) for characterization of lesion detected on whole-body scintigraphy and to train/educate technologist to determine the need of additional SPECT/CT after routine whole-body scan. Materials and Methods: This study group comprised 134 patients, of which 47 were males and 87 females (age range 13-85 years). Between February 2016 and April 2016, 98 bone scans were performed. Out of 134 scans, 51 patients' results showed normal scan and 83 patients' results showed benign, equivocal, or metastatic uptake. Results: Out of 134 scans, 51 patients' results showed normal scan and 83 patients' results showed benign, equivocal, or metastatic uptake. The results of this study show that nuclear medicine technologists, after a period of formal training, are able to decide when an additional SPECT/CT examination is necessary after a whole-body bone scan. Conclusion: With the help of training/education, nuclear medicine technologists are able to determine the need of additional SPECT/CT after routine whole-body scan.
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