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ABSTRACT
Year : 2010  |  Volume : 25  |  Issue : 3  |  Page : 121-126 Table of Contents   

Technical


Date of Web Publication25-Nov-2010

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How to cite this article:
. Technical. Indian J Nucl Med 2010;25:121-6

How to cite this URL:
. Technical. Indian J Nucl Med [serial online] 2010 [cited 2019 Dec 10];25:121-6. Available from: http://www.ijnm.in/text.asp?2010/25/3/121/72766

TEC 01 (ORAL)

Optimisation of acquisition parameters for bremsstrahlung imaging of 89Sr and 90Y

Zade Anand, Jha A, Monterio P, Nair S, Shetye B, Shah S, Rangarajan V


Bioimaging Unit, *Department of Radio Diagnosis, Tata Memorial Hospital, Parel, Mumbai - 400012, India

Introduction: Pure Beta emitters such 89 Sr and 90 Yare preferred therapeutic radiopharmaceuticals as these do not emit primary gamma radiations. Imaging of patients having received these isotope therapies is difficult and can be performed using Bremsstrahlung radiations emitted from the patient. Conventional gamma photon imaging methods cannot be easily applied to imaging of -bremsstrahlung because of its - continuous energy spectrum and a broad spectrum of energies that are not abundant. This makes collimation and energy window selection complex. Aim and objectives: 1) To optimize the imaging parameters including the choice of collimator and spectral energy window for Bremsstrahlung imaging. 2) To identify the appropriate time interval for imaging patients injected with Sr 89 in view of its long half life (50.5 days). Materials and Methods: 6 patients undergoing 89Sr chloride therapy for bone pain palliation from osteoblastic skeletal metastases and13 patients undergoing 90Y radioembolisation of hepatic metastases/Hepatocellular carcinoma were imaged on a dual head gamma camera (GE Infinia Hawkeye) Planar and Tomographic images were obtained with different collimators, different matrices and different time intervals. SPECT /CT imaging was performed using a 64΄64 image matrix for 32 projections over 180ºfor each camera head (a total of 64 projections over 360º) for 20 sec per projection using the auto contour rotation mode. Raw data were reconstructed by filtered back projection in the transaxial, sagittal and coronal planes. The reconstructed slices were one-voxel Thick (9.6 mm). The images were evaluated qualitatively by 3 independent interpreters and best collimator, matrix size, and injection-imaging interval were obtained. Results: For 89Sr bremsstrahlung imaging the best images were obtained with high energy collimator, energy window of 77keV +/- 50%, with injection imaging interval of 7 days and matrix size of 128x 128. For 90Y- bremsstrahlung imaging, the best images were obtained with High energy collimator with an energy window of 140kev - 64.29% and +56% 128x 128 matrix. The best tomographic images were obtained when hamming filter was used. Since 90Y is relatively short lived isotope (physical half life of 2.7 days,) the optimum injection-imaging interval was not necessary and hence not evaluated. Conclusion: Bremsstrahlung imaging of pure beta emitters like 89Sr and 90 Ygive images of reasonably good quality if optimum acquisition parameters are set. These help to overcome the limitation of inability to image the distribution of these tracers.

Keywords: Bremsstrahlung radiation, optimizing imaging, radionuclide therapy

TEC 02 (ORAL)

Experience with dedicated ultra fast solid state cardiac gamma camera: Technologist perspective

Parab Anil, Gaikar Anil, Patil Kashinath, Lele V


Department of Nuclear Medicine and PET - CT, Jaslok Hospital , Mumbai, India

Aim: To describe technologist perspective of working with ultra fast solid state gamma camera and comparison with conventional dual head gamma camera. Material and Methods: 900 Myocardial Perfusion scan were carried out on dedicated solid state detector cardiac camera between 1 st February 2010 till 29 th August 2010. 27 studies were done back to back on a conventional dual head gamma camera. In 2 cases dual head isotope imaging was done (Thallium+99mTc-tetrofosmin).Rest stress protocol was used in 600 patients and stress - rest protocol was used in 300. 1:3 ratio of injected activity was maintained for both protocols (5 mCi for 1 st study and 15 mCi for second study). For Rest - Stress protocol, 5 mCi of 99m Tc - Tetrofosmin was injected at rest, 40 minutes later, 5 min image was acquired on the solid state detector. Patient was then stressed. 15 mCi 99m Tc - Tetrofosmin was injected at peak stress. Images were acquired 20 minutes later for 3 minutes (total duration of study 90 - 100 min). For stress rest protocol, 5 mCi 99m Tc - Tetrofosmin was injected at peak stress. 5 mCi images were acquired 20 minutes later. Rest injection of 15 mCi was given 1 hour post stress injection. Rest images were acquired 40 minutes after rest injection (total duration of study 110 - 120 min). Results: We observed even with lesser amount activity and acquisition time of 5 min/cardiac scan it showed high sensitivity count rate over 2.2 - 4.7 kcps (10 times more counts than standard gamma camera). System gives better energy resolution < 7%. Better image contrast. Dual isotope imaging can be possible. Spatial resolution 4.3 - 4.9 mm. Excellent quality images were obtained using low activities (5 mCi/15 mCi) using 1/3 rd the acquisition time compared to conventional dual head gamma camera Even in obese patients 7 mCi/21 mCi activity yielded excellent images at 1/3 rd acquisition time Quick acquisition resulted in greater patient comfort and no motion artifact also due to non rotation of detectors. Lesser activity dose translated into lesser radiation exposure. Back to back comparison in 20 patients with conventional dual head gamma camera showed comparable images at much lesser activity and acquisition time. Conclusion: Our experience with myocardial perfusion imaging performed with solid state dedicated cardiac camera has been very satisfactory. This detector allows for high quality images at 1/3 rd acquisition time and lesser injected activity with greater patient comfort and throughout and with lesser radiation exposure.

Keywords: Technical experience, Ultrafast solid state detector cardiac gamma camera, low 99mTc-tetrofosmin/MIBI doses-shorter acquisition timings for Myocardial Perfusion scan, Excellent image quality



TEC 03 (POSTER)

The pet biomarker-generator for on-site single dose [ 18 F] fdg0 production

Anthony M Giamis


ABT Molecular Imaging, Knoxville, TN, USA

Aim: To produce [ 18 F]FDG in efficient, single dose quantities and on-site is considered by many to be the holy grail of molecular imaging. To satisfy the need for single dose [ 18 F]FDG with high frequency, reproducibility, and quality in an "on-demand" marketplace requires a new approach for the production of radiopharmaceuticals. Utilizing the latest technologies for material management and product purification, we provide quality [ 18 F]FDG upon request. Materials and Methods: The Biomarker-Generator consists of a lower-energy positive ion particle accelerator, operating with a power consumption that is ten times less than existing PET accelerators, coupled to a disposable card and kit based automated chemistry platform. [ 18 F]Fluoride is produced by the standard p-n reaction with [ 18 O] enriched water. The accelerator operates with 2-5. A beam current. This produces approximately 1 mCi [ 18 F]fluoride per minute. The automated chemistry platform: pumps, reactors, and transport lines meters the required reagents as required for the synthesis of [ 18 F]FDG. The process is completed in under 12 minutes. The [ 18 F]FDG is purified in-line on a disposable cartridge.The typical process involves [ 18 O] water, bombarded for 20 minutes in the accelerator, added to a solution of potassium kryptofix (5.5 mg/mL K 2 CO 3 , 30 mg/mL K 222 ) in acetonitrile. Azeotropic removal of water precedes the addition of mannose triflate solution (25 mg/mL) in dry acetonitrile. The solution is heated for 2 minutes then the solvent is removed in vacuo. Aqueous hydrochloric acid is added to facilitate hydrolysis. The crude product solution is neutralized then purified by passing through an SPE-column, comprised of an anion-exchange resin as well as alumina-N and C18 media, before passing through a sterile Millipore filter (0.22 um) into a sterile syringe applicator.

Results: Azeotropic drying and activation of the [ 18 F]fluoride was complete in 4 minutes. Fluorination and solvent removal was complete after 3 minutes. Hydrolysis, purification, dilution, and compounding was finished in the remaining 4 minutes. The entire process, including bombardment, was finished in 32 minutes. The pre-purification radiochemical yields were 96% [ 18 F]FDG. Residual loss, radioactive material left behind, was less than 7%. The overall radiochemical yield for the 12-minute microchemical process was 79.9%. To demonstrate the stability, robustness, and reproducibility of the Biomarker-Generator, 10 subsequent "single-dose" production runs of [ 18 F]FDG were performed in one day.

Conclusion: We have demonstrated the capability to produce single dose [ 18 F]FDG economically, efficiently, and "on-demand" for both the clinical market and for biotechnology applications.

Keywords: PET, radiotracer, biomarker-generator, [ 18 F]FDG, automated radiopharmacy

TEC 04 (POSTER)

Does 99m Tc MAA study accurately predict the Hepatopulmonary shunt fraction of 90Y Theraspheres?

Jha Ashish, Zade A, Monterio P, Kulkarni S 1 , Kulkarni A 1 , Shetty Nitin 1 , Shah S, Purandare NC, Rangarajan V


Bioimaging Unit, 1 Department of Radio Diagnosis, Tata memorial Hospital, Parel, Mumbai- 400012. India

Introduction: Transarterial-radioembolisation (TARE) is FDA approved therapeutic option for primary and metastatic liver malignancy when patient is inoperable; which in addition to the embolic effect (as seen with Transarterial- chemoembolisation-TACE) also gives the benefit of selectively irradiation to the target lesions with minimal toxicity to adjacent normal hepatocytes. However there is a risk of shunting of radioactive spheres to pulmonary circulation and subsequent pulmonary toxicity if the hepatopulmonary shunt fraction is high. The estimated lung dose becomes the limiting factor for the dose that can be delivered trans- arterially for radioembolisation of hepatic neoplasms.This is achieved by a pretreatment 99mTc MAA study. Aim: The accuracy of 99mTc-MAA Scintigraphy to predict the hepatopulmonary shunt fraction of 90Y Theraspheres was evaluated by comparing it with that obtained by post therapeutic bremsstrahlung imaging. Materials And Methods: Patients: 13 patients who underwent 90Y Theraspheres radioembolisation of hepatic malignancies (both primary and secondary) underwent pre therapeutic 99mTc- MAA Scintigraphy and post therapeutic Y-90 Bremsstrahlung Scintigraphy. 10 - 12 mCi of freshly prepared 99mTc MAA was administered by selective hepatic artery cauterization. Planar and tomographic images were acquired within 1hr of radiopharmaceutical administration. IMAGE ACQUISITION Tc 99m MAA static images were acquired in 256 Χ 256 matrix (1000KCnts) and SPECT were a 128 128 matrix with 64 frames (20 s/frame). The scan parameters for CT were 140 kV, 2.5 mAs, and 1-cm slices. SPECT images were corrected for attenuation and scatter. Post therapeutic 90Ybremsstrahlung imaging was done with HEGP collimator with photo peak centered at 140kev - 64.29% and +56% window width. SPECT/CT images were obtained using a dual-detector gamma-camera with a mounted 1-row CT scanner (Infinia Hawkeye; GE medical systems) to evaluate hepatic and extra hepatic tracer localization. IMAGE PROCESSING and DATA ANALYSIS: Both the sets pre and post therapeutic images were analyzed on dedicated workstation (Xeleris 1.1, GE Medical Systems). Hepatopulmonary shunt was calculated by self customized software developed on Xeleris workstation. Results: 13 patients undergoing -90 Y Theraspheres therapy for radioembolisation of hepatic neoplasm were evaluated. The HPS fraction calculated from pre therapeutic 99m Tc MAA study and post therapeutic -90 Y bremsstrahlung images were 4.09% and 4.28% respectively. There is good correlation in the HPS fraction values by both methods (coefficient of correlation=0.973) CONCLUSION The accuracy of Pre therapeutic 99m Tc MAA study is high in predicting the HPS of 90 Y-Theraspheres.

Keywords: scintigraphy, thyrotoxicosis, 99mTco4-, chemical pollution

TEC 05 (ORAL)

In vitro and In vivo analysis of radiolabeled clindamycin hydrogel gel by radioscintigraphic techniques

Kumar N 1 , Datta M 1 , Chopra MK 1 , Soni NL 1 , Mittal G 1 , Singh T 1 , Bhawna 2 , Bhatnagar A 1

1Institute of Nuclear Medicine and Allied Sciences (DRDO), Brig. S.K. Mazumdar Road, Timarpur, Delhi-54, India. 2 Faculty of Pharmacy, Jamia Hamdard, Delhi-62, India

Acne is one of the common dermatological problems caused by microorganism Acne vulgaris, therefore being used commonly in the treatment of acne. Clindamycin is the 7- deoxy, 7- chloro congener of the lincomycin, a macrolide antibiotic derived from Streptomyces lincolnesis. This study was performed for in-vitro and in-vivo estimation of radiolabeled clindamycin hydrogel using radioscintigraphic techniques for transdermal permeation. Clindamycin was supplied as a gift sample by Glenmark Research Laboratory (Mumbai, India) and other chemicals and reagents used were of analytical grade and were purchased from Merck Chemicals (India). Clindamycin was radiolabeled with 99mTc-pertechnetate using stannous chloride as a reducing agent. Radiolabeled clindamycin was characterized for its stability at room temperature and in physiological conditions (serum). Clindamycin hydrogel was prepared by dispersion of radiolabeled clindamycin in carbopol 980 containing polaxomer as surfactant and methyl paraben as preservative solution. The prepared hydrogel was analysed for in vitro analysis via franz diffusion cell and in vivo studies were performed in balb-C mice for biodistribution and skin permeation and were analysed by radiometry. The results obtained showed labeling efficiency of clindamycin was more than 90%, and that was consistent and the radiolabeled drug was stable upto 24 hrs in serum. In vitro release studies showed an increased release rate till four hours and it's become plateaus after 4 hours. In vivo biodistribution studies were showed Tc-99m clindamycin hydrogel remains stable and follow predominantly hepatic excretion. Biodistribution pattern suggests late redistribution from a storage sight, probably, body fats.

Keywords: Clindamycin, hydrogel, in-vitro studies, radiometry, 99mTc-pertechnetate

TEC 06 (ORAL)

Initial clinical experience with dedicated ultra fast solid state cardiac gamma camera

Aland Nusrat, Lele V


Jaslok Hospital and Research Centre, Mumbai, India

Aim: To analyze the imaging and diagnostic performance of new dedicated ultra fast solid state detector gamma camera and compare it with standard dual detector gamma camera in myocardial perfusion imaging. Material And Methods: In total 900 patients underwent myocardial perfusion imaging between 1 st February 2010 and 29 th August 2010 either stress / rest or rest /stress protocol. There was no age or gender bias (there were 630 males and 270 females). 5 and 15 mCi of 99m Tc - Tetrofosmin / MIBI was injected for 1 st and 2 nd part of the study respectively. Waiting period after injection was 20 min for regular stress and 40 min for pharmacological stress and 40 min after rest injection. Acquisition was performed on solid state detector gamma camera for a duration of 5 min and 3 min for 1 st and 2 nd part respectively. Interpretation of myocardial perfusion was done and QGS / QPS protocol was used for EF analysis. Out of these, 20 random patients underwent back to back myocardial perfusion SPECT imaging on standard dual detector gamma camera on same day. There was no age or gender bias (there were 9 males, 11 females). Acquisition time was 20 min for each part of the study. Interpretation was done using Autocard and EF analyses with 4 DM SPECT. Images obtained were then compared with those of solid state detector gamma camera. Result: Good quality and high count myocardial perfusion images were obtained with lesser amount of tracer activity on solid state detector gamma camera. Obese patients also showed good quality images with less tracer activity. As compared to conventional dual detector gamma camera images were brighter and showed better contrast with solid state gamma camera. Right ventricular imaging was better seen. Analyses of diastolic dysfunction was possible with 16 frame gated studies with solid state gamma camera. Shorter acquisition time with comfortable position reduced possibility of patient motion. All cardiac views were obtained with no movement of the detector reducing camera related motion artifacts. Diagnostic performance was comparable to that of standard dual detector gamma camera images. Mid septum invariably showed perfusion defects in QPS protocol, this probably was due to lack of normal database for solid state detector. Lung activity could not be visualized due to small field of view. Extra cardiac activity could be assessed. CONCLUSION We preferred solid state cardiac gamma camera over conventional dual detector gamma camera for myocardial perfusion imaging. Advantages of solid state gamma camera over standard dual head gamma camera: 1. Faster acquisition time 2. Increased patient comfort 3. Less radiation dose to the patient 4. Brighter images 5. No motion artifact 6. Better right ventricular imaging Disadvantages 1. Extra cardiac activity cannot be assessed 2. Lung activity not seen due to small field of view 3. Invariably septal perfusion defects noted.

Keywords: Clinical experience, Solid state gamma camera, Less activity, Short acquisition time, Good quality images, No motion artifacts, Diastolic dysfunction analysis

TEC 07 (ORAL)

Small animal PET/SPECT-CT: First experiences at ACTREC for preclinical research.

Chaudhari Pradip, GhoshSmall S


Animal Imaging Facility, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Kharghar, Navi Mumbai-410210, India

Small laboratory animal models are being used increasingly as research tools in several human diseases such as cancer, cardiovascular diseases, endocrine disorders and obesity. Hence dedicated Imaging modalities such as microPET (Positron Emission Tomography), microSPECT (Single Photon Emission Computed Tomography) and microCT (X-ray Computed Tomography) have emerged for in-vivo imaging of animals. Over the last couple of years molecular and functional imaging has become a powerful approach for studying spatial and temporal distribution of new drugs and their target affinity non-invasively in animal models. ACTREC has established a preclinical PET/SPECT-CT facility very recently and facility is functional since last few months. During this period the approval for the layout design of facility and authorization for procuring radioisotopes has been obtained from the regulatory authority. The facility has got FLEX trumph trimodality PET/SPECT/CT platform from WIPRO GE, India. Laboratory animals such as mouse, rat and hamsters; which are commonly used in cancer research as well as new drug discovery studies can be imaged. More than 30 PET studies using 18F-FDG, 18F-FLT, 18F-NaF in normal and tumor bearing animals were performed. Simultaneously the more than 110 CT studies performed utilizing various living and non-living subjects. The PET and CT performed on mice and rats were fused together for studying the tracer distribution on anatomical map. ACTREC has established this facility to stimulate multidisciplinary approach in translational research.

Kewwords: Small Animal Imaging, microPET, microSPECT, microCT and preclinical imaging

TEC 08 (POSTER)

PET Imaging Clinical Trials: Standards for Good Image Quality

Ratna Pranav


Medical Diagnostics, GE Healthcare.

Imaging holds a promising place in the drug development process and clinical trials. In recent times, scientists and researchers have realized that imaging enables them to look for new surrogate endpoints and accelerate the process of drug development.As the number of such trials is increasing every year, there is a growing awareness for the need of quality in imaging trials, so as to avoid imaging issues, reduce losses due to non-evaluable imaging and improve subject safety. This paper is an attempt to address the need of standards for good quality image in clinical trials which use imaging. The main focus of the paper is to describe the various acquisition options in PET-CT available for medical imaging, their applicability in drug development process and clinical trials, emphasize the need to identify possible sources that could possibly impact the quality of images, ways of standardizing the equipments and minimizing the variability of different scanners. Additionally this paper will look into the importance of an expert medical imaging group, imaging protocols, quality assurance programs, and image assessment post acquisition for technical compliance and image quality. A reference of standards as prescribed by various scientific bodies and organizations will also be reviewed. In this paper the focus will be mainly to discuss aspects of PET-CT imaging in clinical trials. PET-CT has the potential to be best for response monitoring to therapy and early detection of disease compared to all other imaging modalities such as CT, MRI, gamma camera, SPECT, ultrasonography etc. In research, PET imaging can help in understanding the pharmacokinetics of a molecule, i.e. kinetic modeling and provides various imaging options, qualitative and quantitative. PET-CT provides anatomical as well as functional information and has the potential to be highly reproducible. The paper emphasizes good imaging practices and its relevance, especially when we are not just restricted to FDG PET-CT imaging, but look forward towards development and application of new PET radiopharmaceuticals. An example of one of these novel radiopharmaceuticals is [ 18 F]fluciclatide, which detects angiogenesis via the expression of αvβ3 integrins (Mena et al, 2010). Phase 2 global multi-centre studies are current underway evaluating this radiopharmaceutical and two clinical trial sites in Bangalore, India will commence recruitment in the near future. Clinical trial data from these studies will be presented to highlight the need for good image quality in clinical trials.

Keywords: PET-CT, image quality, trails

TEC 09 (POSTER)

Sterile sodium pertecnetate-99mTc from Geltech generator

Sarkar SK, Kothalkar C, Naskar P, Vispute GL, Joshi S, Saraswathy P, Dey AC, Meera V


Board of Radiation and Isotope Technology (Brit), Barc Vashi Complex, Navi Mumbai-400705, 1 Radiopharmaceutical Division, Bhabha Atomic Research Centre(Barc), Mumbai-400085, India

99mTc eluted from the Geltech generator supplied by BRIT with sterile and pyrogen free 0.9% NaCl solution is presently not claimed as sterile. Further sterilization of Na99mTcO4 is an essential requirement for formulation of 99mTc-radiopharmaceuticals for patient administration. This is done presently by the users, either by passing through disposable sterile 0.22μ membrane filter or autoclaving the product at 121ºC for 30 minutes at 15 psi. Sterile 0.22μ membrane solution filter normally available can be used for a single elution only as air film formed over them makes them impervious to further elution. To enable repeated passage of saline for elution, a special type online 0.22 μ membrane filter has been identified and adapted in Geltech generator for online filtration of 99mTc to obtain sterile sodium pertechnetate. The speciality of the membrane is that it is composed of both hydrophilic and hydrophobic membrane housed in the same filter assembly permitting repeated passage of saline and air. Thus a single filter can be used unchanged throughout the generator shelf-life. Eighty five 99mTc eluates were collected using this filter from 8 batches of Geltech generators without any difficulties. These were evaluated for sterility and pyrogenicity. All the eluates were found to be sterile. The Geltech generator system with modified filtration assembly can be used in hospital radiopharmacy for obtaining sterile and apyrogenic 99mTc-sodium pertechnetate.

Keywords: STERILE 99mTc, GELTECH GENERATOR

TEC 10 (POSTER)

The Journey: From X-Rays to PET-MRI

Tariq Hussain Sheikh


Technologist Spiral CT-MRI Center, Sec 44-C, Chandigarh, India

Medical imaging has undergone remarkable evolution over the past century. Since the discovery of the x-rays by (Wilhelm Conrad Rφentgen), static emission tomography (Hal Anger) computed tomography (Godfrey Hounsfield and Alan Cormack), and magnetic resonance imaging (Paul Lauterbur and Peter Mansfield) there have been many other important discoveries and technical developments that have culminated in our current sophisticated multi-modality imaging systems. Nobel Prizes have been given for the discoveries of radioactivity (Marie Curie, Pierre Curie, and Henri Becquerel in 1903) and the positron (Carl Anderson in 1936) and for technical developments such as the radiotracer concept (George De Hevesy in 1943). Positron emission detection systems have developed since their first use in the 1950s to the high-resolution, high-sensitivity tomographic devices that we have today. In keeping pace with these milestones in the evolution of medical imaging, positron emission tomography (PET), and more recently integrated positron emission tomography-computed tomography (PET-CT), have now emerged not only as important research tools but also as significant diagnostic imaging systems in clinical medicine. The use of multi-modality imaging systems and "smart" specific imaging agents will achieve the key task of accurate diagnosis, treatment evaluation, surveillance, and prognosis in individual patients.PET-CT instrumentation has continued to evolve rapidly, especially over the last decade A PET scanner is combined with a CT scanner into a single machine. The PET and CT components are mounted on the same aluminium support with the CT on the front and PET at the back. Metabolic information is obtained from the PET scanner (emission of annihilation photons) and anatomic information is obtained from the CT scan (transmission of X-Rays). In addition, the CT scan can be used to provide information needed for attenuation correction. The current generation of PET-CT scanners has a common patient palette (bed), which travels from the CT gantry to the PET gantry. These advancements have led to better image registration and higher patient throughput.With further developments in crystal design, time of flight processing, CT based partial volume correction, multi-detector CT, short breath holding times, respiratory gating and newer reconstruction algorithms. PET-CTs of today have reached an unprecedented resolution reaching 2 mm across the field of view in the PET component with sub millimeter resolutions in CT. In short we have reached a long way over the last century, from X-Rays to the inception of PET-MRI, the only hindrance is the availability and high cost which we hope will improve in the days to come.

Keywords: Medical imaging, PET-CT, PET-MRI, Instrumentation

TEC 11 (POSTER)

Effective renal plasma flow using 99mTc-EC by gamma camera and plasma methods: A comparative study

Jain Kinnri, Sarika, Singh B


Department of Nuclear Medicine, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh-160014, India

The nuclear medicine techniques are mostly utilized for functional renal imaging and quantification, often providing information not possible with the conventional radiological modalities. The ability to quantify function by Effective Renal Plasma Flow and Glomerular Filtration Rate can provide a better measurement of functional status than standard laboratory tests such as creatinine clearance. Objectives: The present study was designed to evaluate the absolute ERPF values by multiple plasma sample method (Russell's method) and Gamma camera method (Modified Gates method) using 99mTc-EC and to compare the values of ERPF derived by two methods for the evaluation of correlation if any or if the values by two methods could be used interchangeably. Methodology: In this study, 15 adult patients (9M: 6F, mean age 26.0 ±11.6 years; range 18-66 years) were analysed, who were referred to the Department of Nuclear Medicine (Post Graduate Institute of Medical Education and Research, Chandigarh) for the evaluation of renal function using 99mTc-EC renal scintigraphy. Pregnant or lactating female patients were excluded from the study design. 99mTc-L, L-ethylene dicysteine (EC) was prepared according to manufacturer's instructions under sterile environment. 99mTc-EC (111- 185 MBq) was injected intravenously into the patient's veinflon. Dynamic and static images were acquired with the help of Gamma Camera (GE Millenium) and ERPF was evaluated using Modified Gates Method. For the Plasma Sample Method, Seven serial heparinised blood samples were withdrawn at an interval of 30 minutes, 60 min, 90 min, 120 min, 150 min, and 180 min after the administration of the radiopharmaceutical. ERPF was estimated by the method proposed by Russell et al. An open single compartmental model was used to determine the plasma clearance. Non-Parametric Spearman's test was used to study the correlation and regression in the data. Significance level was analysed using ANOVA test. Results: The normalized value of ERPF as calculated by the Plasma Sample Method was found to be 332.086±164.619 ml/min/1.73m2 BSA. The mean value of normalized ERPF as evaluated by Gamma Camera Method was found to be 417.57±153.94ml/min/1.73m2 BSA. A positive correlation (r=0.76) was observed between the two sets of data which was not significant (p=0.0009). The mean ERPF as evaluated by Gamma Camera Method were found to be significantly higher (by a factor of 1.25) than the Plasma Sample Method. Conclusion: Plasma clearance method is an established gold standard to measure the ERPF values. Gamma Camera overestimates (by a factor of 1.25) the

Keywords: Effective renal plasma flow, Tc-99m EC, gamma camera & plasma sample method

TEC 12 (POSTER)

Donor evaluation of extended time 99m-TcDTPA renal scintigraphy for added information to guide donor kidney selection: A technologist perspective

Chanchala Kale, Sunita Tarsaria, Jaiswal R, Amrita, Roshni, Pallavi


Department of Nuclear Medicine t. Bombay Hospital and Research Centre, Mumbai, India

Introduction: 99m Tc-DTPA renal scan exposes the patient to considerably less radiation and the images are of superior quality. In donor patients a short time renal scintigraphy to calculate GFR by gates formula is widely accepted in clinical practice. Apart from kidney GFR, renal scan gives added information regarding size, shape and position of kidney, perfusion, peaking time, peak to T 1/2 ratio, transit time, perfusion, split function, assessment of drainage pattern. Aim: The purpose of this study was to evaluate significance of extended time 99mTc DTPA renogram for appropriate selection of donor kidney. Materials and Method: A retrospective study on 66 patients (female-40, male-26, age range-22years-70years, mean 48+/- 24) was carried out in our centre. Patients were adequately hydrated before the study. Diuretic intervention renal dynamic scintigraphy (F+10) was performed after administering 5mCi of DTPA intravenously. Sequential dynamic images (Phase I-2 sec/frame for 1 min, Phase II-1min/frame for 29 min)were acquired posteriorly on GE Millennium VG gamma camera. Pre and post syringe counts were also taken. Standard protocol was used for processing. Along with other parameters GFR by Gates formula was obtained Result: GFR was found to be in the range of 68.7 ml/min - 135.8 ml/min.(mean GFR = 102.25 ml/min)It was found that in 50 patients (75%)both Kidney GFR was normal. Whereas in 2 patients (3.0%) global GFR was low. There were 7 patients (10.60%) in which pelvicalceal hold up was seen which adequately cleared with lasix. One patient (<1%) mobile right kidney was found. Small sized left and right kidney was found in 3 (4.54%) and 4(6%) patients respectively. Left and right kidney preserved function (delayed peaking time /delayed clearance) was found in 10 (15.5%) and 5(7.6%) patients respectively. Conclusion: 99mTc-DTPA renal scintigraphy with diuretic (F+10,30min study) as a functional modality is significantly useful in the selection of donor kidney.

Keywords: 99mTc DTPA renal scintigraphy, donor kidney selection

TEC 13 (POSTER)

Development of dual-function SPECT and CT probe for small animal imaging.

Gambhir Sanjay, Ahmad Absar 1 , Dube Veeresh, Kheruka Subash, kumar Uttam


Department of Nuclear Medicine SGPGIMS, Lucknow -226014, India

Different biological queries require different imaging Strategies. In imaging this is more dependent not so much on the instruments but on the properties of the imaging agents.The development of dual-function probes for both fluorescence imaging and MRI was recently reported. Nano SPECT-CT, Bioscan system for animal imaging recently procured by our institute motivated us to explore and standardize a dual function probe for such a system. The study has been planned with a view develop a dual capability CT and radiopharmaceutical contrast to facilitate an anatomical and functional images thus combining the good resolution abilities of CT and high sensitivity functional images of SPECT. Method: Radiolabeling, of Bismuth nanocolloid with Technetium-99m was done and confirmation of good binding by instant thin layer chromatography (ITLC) confirmed more than 90% binding. This was injected into male Sprauge Dawley rats and biodistribution image and clearance time from blood was calculated. Confirmation, of Bismuth nano-colloid to act as CT contrast agent was done by performing phantom study at various concentrations in saline, 50 mg/ml, 100mg/ml, 200mg/ml and 500mg/ml at CT tube current of 2.5mA and tube voltage of 140 KVp. Results: As compared to commercial Iodine contrast (375mg/ml iodine) which was used as standard the average clearance time Bismuth colloid was longer. Its biodistribution was seen in heart, Liver, spleen and kidney. The iodine comparable CT contrast was achieved by 500mg/ml of Bismuth colloid. 99mTc-Bismuth colloid imaging on a dedicated animal SPECT-CT (Nano-SPECT, Bioscan) revealed similar biodistribution and in-vivo-stability of labeling. Conclusion: Successful radiolabeling, in-vivo stability and SPECT imaging of 99mTc-Bismuth colloid along with its potential to impart iodine equivalent contrast raises the possibility of converting 99m-Tc-Bismuth as dual SPECT-CT probe for obtaining functional and anatomical image in pre-clinical setting.

Keywords: Dual-probe, small animal imaging, SPECT-CT

TEC 14 (POSTER)

Effect of beam hardening by using additional copper filter on low dose CT

Kheruka SC, Naithani UC 1 , Maurya AK 2 , Painuly NK 3 , Aggarwal LM 4 , Gambhir S


Dept. of Nuclear Medicine, 2 Dept. of Radiotherapy, SGPGIMS, Lucknow, 1 Dept. of Physics, HNB University Srinagar 3 Dept. of Radiotherapy, CSMMU, Lucknow, 4 Department of Radiotherapy and Radiation Medicine, IMS, BHU, Varanasi

The output of the x-ray tube used in CT provides a spectrum of photon energies from 0 keV up to the maximum photon energy (kVp = peak energy in keV) setting used for the acquisition. Because low-energy photons are preferentially absorbed in tissue, the beam spectrum shifts toward the higher energy end as it passes through more tissue, thereby changing its effective attenuation coefficient and producing a variety of artifacts (beam-hardening effects) in images, and filtering of the beam to remove low-energy photons is required. Aim and Objective: In the present study we attempted to minimize the beam hardening effects by the use of additional copper filter in the x- ray beam and see its effect on the resulting CT images. This study was performed on dual head SPECT (HAWKEYE 4, GE Medical) with low dose CT which acquires images at peak voltages of 120/140 KV and tube current of 2.5 mA. For the evaluation of image quality we used CT QA Phantom (PHILIPS). The CT scanner was recalibrated before acquiring each set of images with individual copper filters. The images were acquired without and then successively with copper filters of different thicknesses. The x - ray tube parameters were kept same as with unfiltered x- ray beam. Moreover Jaszak's SPECT phantom after removing the spheres was used to see the different contrast intensities by inserting the different contrast materials of iodine and bismuth in water as background media. Images were analyzed for visibility, spatial resolution and contrast. Successive improvement in the image quality was noticed when we increased the filter thickness from 1 to 3 mm. The images acquired with 3 mm filter appeared almost with no artifacts and visibly sharper. A degradation in the image quality was noticed when we increased the filter thickness further. The spatial resolution for image matrix of 512 x 512 was found 1.29 mm, 1.07 mm, 0.64 mm and 0.54 mm for without filter, 1mm, 2mm and 3 mm filter respectively. The image quality was further analyzed for signal-to-noise ratio (SNR). It was found to be 1.72, 1.78, 1.98 and 1.99 for open, with 1, 2 and 3 mm filters respectively. This shows that 3 mm filter results an improvement of 15.7% in SNR. Conclusion: On the basis of this preliminary study, we conclude that use of 3 mm copper filter to harden the x - ray beam of low dose CT is optimal for removing the artifacts without causing any significant reduction in the photon flux of the resulting x - ray beam.

Keywords: Filter, Beam Hardening, Artifacts, Attenuation Coefficients

TEC 15 (POSTER)

Comparison of elution efficiency of 99Mo/99mTc generator using theoretical and a free web based software method

Kiran Kumar JK, Sharma S, Chakraborty D, Singh B, Bhattacharaya A, Mittal BR, Gayana S


Postgraduate Institute of Medical Education and Research, Department of Nuclear Medicine, Chandigarh, India

Introduction
: Generator is constructed on the principle of decay growth relationship between a long lived parent radionuclide and short lived daughter radionuclide. Difference in chemical properties of daughter and parent radionuclide helps in efficient separation of the two radionuclides. Aim and Objectives: The present study was designed to calculate the elution efficiency of the generator using the traditional formula based method and free web based software method. Materials and methods: 99Mo/99mTc MON.TEK (Monrol, Gebze) generator and sterile 0.9% NaCl vial and vacuum vial in the lead shield were used for the elution. A new 99Mo/99mTc generator (calibrated activity 30GBq) calibrated for thursday was received on monday morning in our department. Generator was placed behind lead bricks in fume hood. The rubber plugs of both vaccum and 0.9% NaCl vial were wiped with 70% isopropyl alcohol swabs. Vacuum vial placed inside the lead shield was inserted in the vacuum position simultaneously 10 ml NaCl vial was inserted in the second slot. After 1-2 min vaccum vial was removed without moving the emptied 0.9%NaCl vial. The vaccum slot was covered with another sterile vial to maintain sterility. The RAC was measured in the calibrated dose calibrator (Capintec, 15 CRC). The elution efficiency was calculated theoretically and using free web based software (Apache Web server (www.apache.org) and PHP (www.php.net). Web site of the Italian Association of Nuclear Medicine and Molecular Imaging (www.aimn.it). Results: The mean elution efficiency calculated by theoretical method was 93.95% +0.61. The mean elution efficiency as calculated by the software was 92.85% + 0.89. There was no statistical difference in both the methods. Conclusion: The free web based software provides precise and reproducible results and thus saves time and mathematical calculation steps. This enables a rational use of available activity and also enabling a selection of the type and number of procedures to perform in a busy nuclear medicine department.

Keywords: Elution Yield, calculation, software VS theoretical way






 

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