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More than one center of ossification is frequently found in asymptomatic children and adolescents and is regarded as a normal variant. Accessory navicular bone is one of the supernumerary ossicles in the foot. It may present incidentally or may be present with clinical manifestations. Radiograph is non diagnostic in symptomatic cases. 99mTc MDP bone scan shows focal intense uptake. Advantage of three phase bone scan over single delayed skeletal phase in the diagnosis of symptomatic accessory naviculars and it's clinical significance in foot pain was retrospectively analyzed in ten cases of accessory naviculars (five unilateral and five bilateral) in the present study. Bone scans were correlated with radiographs. Intense hyperemia in initial phase and focal intense uptake in delayed phase was taken as characteristic feature for symptomatic accessory navicular. All the symptomatic accessory naviculars (100%) showed positive three phases. Only two out of eleven asymptomatic accessory naviculars (18%) showed positive hyperemia in the initial phase whereas rest showed absence hyperemia. Our study concluded that additional vascular & bloodpool phases improve sensitivity and specificity in diagnosing symptomatic accessory navicular as the main cause of foot pain.

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Positron emission tomography (PET) has been playing key role in important clinical decision-making in many areas ever since its inception in the field of medical imaging. Most of the hospitals are enthusiastic for including PET in their imaging services because of its increasing application particularly in oncology. However, the occupational workers are apprehensive about the risk of higher radiation exposure in a PET facility. There is a need therefore to make the staff aware of the radiation doses they may likely get while working in this facility. We have estimated the radiation exposure to the physicians and technologists working in our PET/CT facility based on the dose rate measurement with calibrated survey meter and pocket dosimeter. The mean dose measured at the chest level per PET/CT procedure was 3.24 μSv and 0.62 μSv for the physicians and technologists respectively. The mean dose to the physicians per MBq of 18F-FDG injected was 8.76 nSv/MBq and 27.68 nSv/MBq at the chest and wrist levels respectively.

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Caffey's disease is not a common clinical occurrence; it often poses problems in diagnosis due to its close resemblance to osteomyelitis. Initial plain radiographic diagnosis is sometimes fraught with the limitation of not being able to differentiate it from chronic osteomyelitis. Skeletal scintigraphy is sensitive in localizing the disease activity to the radiological features of the affected regions and the characteristic location of the lesions helps make the diagnosis without resorting to biopsy and further workup.

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Bone scintigraphy is routinely performed to identify bone and joint abnormalities in patients with low back pain.Urinary contamination by radiotracer excreted through the renal route may complicate scan interpretation, especially when localized to the symptomatic anatomical region. We present such a case where urinary contamination simulating a bony abnormality on the planar image was clearly identified only on SPECT.

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Background : Two most important causes of portal hypertension are cirrhosis of liver and non-cirrhotic portal fibrosis (NCPF). The purpose of this study was to assess the scintigraphic appearances of Tc99m sulfur colloid liver scan in differentiating liver cirrhosis from NCPF. Materials and Methods: Retrospective analysis records of 146 patients (91 male and 55 female) with diffuse hepatocellular disease was done for liver size, liver uptake, spleen size, spleen uptake, colloid shift to bone marrow and lungs. Results: Cirrhotic livers showed patchy and lower uptake than NCPF (59% vs. 20%, P-value 0.041). Spleen size was significantly increased in NCPF compared to cirrhosis (100% vs. 67%, P-value 0.0137). Significant colloid shift to bone marrow was noted in cirrhosis (84% vs. 7%, P-value<0.0001). Conclusion: Tc99m sulfur colloid liver scan is a non-invasive procedure having a useful adjunctive role in clinical differentiation of cirrhosis from NCPF.

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Background The proper localization of a hypersecreting parathyroid gland is of vital importance for successful unilateral neck exploration (UNE) and parathyroidectomy. Aim: In this study we aim to evaluate the (99mTc) sestamibi parathyroid scan as a single localizing modality, and we also assess its relation to the weight of the gland and to the preoperative parathyroid hormone (PTH) levels. Patients and Methods: We reviewed 170 patients from our hospital (Notre-Dame hospital) from 2005 to 2008, with a mean age of 56.6 years and a female to male ratio of 3.3:1. With primary hyperparathyroidism, all of them had (99mTc) sestamibi parathyroid scan for the localization of the parathyroid adenoma. Preoperative and postoperative PTH levels were recorded. The histopathology reports confirmed the diagnosis and weight of the diseased gland, which were recorded every time. The results were analyzed and correlated with the sestamibi results, to evaluate its accuracy. Results: Seventy-eight patients (41%) of the 170 had an exact match (EM) sestamibi results,81 (51.6%) had a partial match, and only 11 patients were reported as mismatch. Analyzing the mean weight of the gland in each group between matching (EM, PM) versus mismatch resulted in a mean difference of 0.823 g (1.05 and 0.247 g, respectively) P = 0.045. Hyperplasia to adenoma ratio was more in the partial matching group (18.5%) versus the exact matching group (7.6%). Finally the mean PTH level was higher in the EM group (28.8 pmol/L) compared to the mismatch group (10.1 pmol/L) P = 0.02. Overall sensitivity and specificity for the (99 mTc) sestamibi in our data was 98.1 and 97%, respectively. Conclusion: (99mTc) sestamibi is a highly accurate test that can be employed as a single localizing modality for identifying a hypersecreting parathyroid, a UNE, or a parathyroidectomy.The weight of the gland plays an important role in the accuracy of the test, as also the preoperative PTH levels.

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Objectives : This paper addresses a comparison between physical dosimetry and mathematical dose calculation in nuclear medicine. Materials and Methods: Dose rate was calculated by mathematical external dose calculation formula and by physical dosimetry from the surface of 38 adult patients' body referred to nuclear medicine department. Results of the methods were compared and correlation and regression tests were also performed. Results: Although the physical dosimetry data in this study are in good consistency with other researches, they are much lower than the results of mathematical dose calculation formula. The correlation coefficient between measured dose rate with calculated values derived by mathematical formula was found to be 0.852 (P value=0.148). Conclusion: It seems that physical dosimetry data are more accurate than the results of mathematical dose calculation. In case of using mathematical dose calculation formula, other correction factors should be considered and applied for getting reliable data.

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Background : Developmental structural abnormalities of the thyroid gland are relatively rare. There are scanty reports of hemiagensis, dual and triple ectopia of the thyroid in the literature Materials and Methods: We did a retrospective analysis of 236 patients referred to us for Tc-99m Pertechnetate thyroid scan over period of four months (May 2010 to Sept 2010). Twenty of these 236 patients aged less than 20 years found to have developmental abnormality of the thyroid gland on thyroid scan. Diagnosis was correlated with anatomical imaging (USG/CT scan), fine needle aspiration cytology (FNAC) and histopathology. Results : Out of the 20 patients, 8 were diagnosed with thyroglossal cyst, 4 with ectopic thyroid gland, 4 with dual ectopia, two had agenesis of thyroid gland, one case each with hemiagenesis and triple ectopia. Conclusion: The study has emphasized the indispensable role of Tc-99m Pertechnetate thyroid scan in the evaluation of midline neck swellings of childhood and diagnosing developmental anomalies of thyroid gland.

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Intraperitoneal administration of diltiazem (DTZ), half an hour prior to whole-body gamma irradiation (5.0 Gy), showed the protection of animals from radiation-induced micronuclei in bone marrow. The frequency of micronuclei elevated from 6 to 24 hrs. post-irradiation in both irradiated groups but declined thereafter. The counts of micronuclei were found to be significantly lower in DTZ treated irradiated group and it restored to normal on 7th day, while the normal number of micronuclei observed in control group only after 28 days post-irradiation. These data demonstrate that DTZ protects mice bone marrow against radiationinduced micronucleus formation.

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Objective : To measure the radiation exposure to nuclear medicine personnel during synthesis and injection to the patients of Ga-68 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (DOTA)-1-Nal ³ -octreotide (NOC)- (DOTA-NOC) using ring thermoluminescence dosimeters (TLDs). Materials and Methods : Synthesis of Ga-68 DOTA-NOC was done on a semi-automated system. Finger doses were measured during synthesis and injection of Ga-68 DOTA-NOC. The occupational workers wore TLDs at the base of ring finger of both hands. The finger doses of two radio chemists were measured during synthesis of Ga-68 DOTA-NOC while that of a physician during its injection to the patients. Results : Duration of the study was eight months and a total of 20 samples were prepared. During synthesis, the mean dose to base of left ring finger was 3.02 ± 1.01 mSv and to base of right ring finger was 1.96 ± 0.86 mSv. Mean dose to base of left ring finger was 1.26 ± 0.35 mSv while that to base of right ring finger was 1.03 ± 0.13 mSv during injection. The mean dose was observed to be higher during synthesis than injection. However, the difference was not significant (P = 0.27 and P = 0.18, respectively). Overall mean finger dose of left hand was 2.43 ± 1.21 mSv, whereas for the right hand the same was 1.65± 0.82 mSv. Conclusion : Finger doses to radio chemists during semi-automated synthesis of Ga-68 DOTA-NOC and that to the physician involved in injection of Ga-68 DOTA-NOC were found to be within permissible limits. Ring dosimeters must be worn for the safety of the nuclear medicine personnel involved in synthesis and injection of Ga-68 DOTA-NOC.

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Background : A variety of neurodegenerative disorders produce significant abnormal brain function which can be detected using fluorodeoxyglucose positron emission tomography (FDG PET) scan even when structural changes are not detected on CT or MRI Scan. A study was undertaken at our institute to evaluate the FDG PET/CT findings in Indian population suffering from mild cognitive impairment (MCI), Alzheimer's disease (AD), fronto-temporal dementia (FTD), dementia with lewy body disease (DLBD) and other miscellaneous causes of dementia. Materials and Methods : 117 0 subjects having neurocognitive deficits and 36 normals were included in our study. All patients underwent a detailed history and clinical examination. This was followed by a mini mental state examination. Subsequently an FDG brain PET scan and an MRI were done. Results :In the patient population included in our study group 36 were normal, 39 had MCI, 40 had AD, 14 had FTD, and 13 had DLBD and 11 dementia due to other miscellaneous causes. MCI patients showed primarily reduced tracer uptake in the mesio-temporal cortex. AD patients showed reduced tracer concentration in temporo-parietal lobes, while patients with advanced diseases showed frontal lobe disease additionally. In subjects of FTD, reduced radiotracer uptake in the fronto-temporal lobes was noted. In addition, FTD patients also showed basal ganglia defects. In contrast the DLBD patients showed globally reduced FDG uptake including severely affecting the occipital cortices. Conclusion :In the current study the F18-FDG PET scans have been shown to be highly useful in the diagnosis of various neurocognitive disorders of the brain. AD was found to be the most common dementia in the Indian population followed by MCI. Diffuse Lewy body disease, FTD and other miscellaneous categories of dementia had a near similar incidence.

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Background: The output of the X-ray tube used in computed tomography (CT) provides a spectrum of photon energies. 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. Filtering of the beam may be used to remove low-energy photon component. The accuracy of attenuation coefficient calculation by bilinear model depends highly upon accuracy of Hounsfield units. Therefore, we have made an attempt to minimize the beam-hardening effects using additional copper filter in the X-ray beam. The quantitative evaluation were made to see the effect of additional filters on resulting CT images. Materials and Methods: This study was performed on dual-head SPECT (HAWKEYE 4, GE Healthcare) with low-dose CT which acquires images at peak voltages of 120/140 kV and a tube current of 2.5 mA. For the evaluation of image quality, we used CT QA Phantom (PHILIPS) having six different density pins of Water, Polyethylene, Nylon (Aculon), Lexan, Acrylic (Perspex) and Teflon. The axial images were acquired using copper filters of various thicknesses ranging from 1 to 5 mm in steps of 1 mm. The copper filter was designed in such a manner that it fits exactly on the collimator cover of CT X-ray tube. Appropriate fixation of the copper filter was ensured before starting the image acquisition. As our intention was only to see the effect of beam hardening on the attenuation map, no SPECT study was performed. First set of images was acquired without putting any filter into the beam. Then, successively, filters of different thicknesses were placed into the beam and calibration of the CT scanner was performed before acquiring the images. The X-ray tube parameters were kept the same as that of unfiltered X-ray beam. All the acquired image sets were displayed using Xeleris 2 (GE Healthcare) on a high-resolution monitor. 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. Results: 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 were visibly sharper. Lower energy photons from X-ray beam cause a number of artifacts, especially at bone-tissue interfaces. Additional filtrations removed lower energy photons and improved the image quality. Degradation in the image quality was noticed when we increased the filter thickness further to 4 and 5 mm. This degradation in image quality happened due to reduced photon flux of the resulting X-ray beam, causing high statistical noise. The spatial resolution for image matrix of 512 × 512 was found to be 1.29, 1.07, 0.64 and 0.54 mm for without filter, with 1, 2 and 3 mm filters, 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 in an improvement of 15.7% in SNR. Conclusion: On the basis of this study, we could conclude that use of 3-mm copper filter in the X-ray beam is optimal for removing the artifacts without causing any significant reduction in the photon flux of the resulting X-ray beam. We also propose that as artifacts have been removed from the images, the value of Hounsfield units will be more accurate and hence the value of attenuation coefficients lead to better contrast and visualization of SPECT images.

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A 18-year-old male presented with low back ache. The patient was investigated and was diagnosed to have painful scoliosis. X-ray and other examinations could not reveal any diagnosis. The patient was referred to undergo bone scan on clinical suspicion of osteoid osteoma and to rule out stress fracture if any. Planar bone scan was performed, which showed a lesion in L3 vertebra and was further evaluated with SPECT (Single photon emission computed tomography) study to characterize the lesion. On SPECT examination, the classical features of osteoid osteoma, the double density sign (11), was noted in the pars interarticularis region. These findings were confirmed by a CT scan, which showed a sclerotic lesion in pars interarticularis of L3 vertebra. The patient was posted for operation and was relieved of symptoms in the postoperative follow-up.

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We present a 40-year-old male who had myocardial infarction (MI), 48 hours following a road traffic accident. EKG showed anterior wall MI and complete heart block. Tc99m-Pyrophosphate scan and angiography confirmed the diagnosis. The possibility of traumatic MI should be considered in cases of chest trauma and the patient should be observed for 48 hours. Pyrophosphate scintigraphy can be useful in these patients.

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Hematopoietic stem cells (HSC), which are responsible for maintaining continuous pool of blood cells, are being used for bone marrow transplantation (BMT). However, the programmed cell death/ apoptosis poses a serious problem for their optimum proliferation and differentiation after radio- and/ or chemotherapy. The role of Bcl-2 (B Cell Lymphoma) protein, a Bcl-2 family member, is well established in suppressing apoptosis of HSC on irradiation and serum withdrawal. The anti-apoptotic activity of Bcl-2 is regulated by inter- and intra-family homo-/ heterodimerization. Here we are proposing that the potential of Bcl-2 and its survival enhancing mutants, such as D34A and S70E, may be harnessed (gene therapy) to suppress the radiation and growth factor withdrawal induced apoptosis provided the neoplastic outcomes of these genes are regulated. The suggested hypothetical model is likely to be helpful in treating blood borne disorders and radiation injury through BMT.

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The management protocol for differentiated thyroid cancer includes whole body iodine-131 imaging, to detect residual thyroid tissue and distant metastasis, after thyroidectomy. However, the diagnostic dose of radioiodine may fail to detect the non-functioning or poorly functioning metastasis. We present a case where hybrid single photon-emission computed tomographic and computed tomographic (SPECT-CT) fusion imaging, using a diagnostic dose of iodine-131, was able to detect both functioning as well as non-functioning pulmonary metastases, prior to high-dose radioiodine therapy.

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Development of hyperbilirubinemia, concurrent or subsequent to hyperthyroidism, can be due to thyrotoxicosis per se, or due to drug treatment of hyperthyroidism. Other rare conditions: autoimmune thyroid disease, or causes unrelated to hyperthyroidism like viral hepatitis, alcohol abuse, sepsis, cholangitis, or as a side effect of certain medications. In this article, we review these causes of co-existent hyperthyroidism and jaundice. We also highlight the changes to be expected while interpreting thyroid function tests vis-a-vis liver function tests in this subgroup of patients.

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