Background: Prostate cancer is biologically and clinically a heterogeneous disease that makes imaging evaluation challenging. One of the important challenges in this cancer is to detect recurrent disease. Biochemical response using Prostate Specific Antigen (PSA) and Imaging using several PET tracers have poor sensitivity and specificity. Therefore, we analyse the role of Ga68-PSMA (Prostate Specific Membrane Antigen) imaging in prostate cancer, which is a new PET tracer. Methods: In this study, we evaluated PET scans of 262 patients with diagnosis of prostate cancer. These patients were scanned using Ga68-PSMA for either staging or response evaluation. Results: 336 PSMA scans were performed. Ga68-PSMA scan resulted in the detection of extra-prostatic disease in 53.2% of cases when done at baseline before commencing any treatment. The sensitivity of Ga68-PSMA at baseline with histopathological diagnosis was 95% with 95% CI ranging from 86% to 98%. The positive predictive value was high at 98% with 95% CI ranging from 91% to 99%. In 26 (10%) patients who had surgical castration, Ga68-PSMA scan was able to detect disease progression / castration resistance in 100% of cases. The outcome of castration-resistant prostate cancer was compared with other cases where castration was not done. In those who did not undergo castration, there was a significantly better response by hormone therapy (p = 0.03) and radiotherapy (p = 0.01) on Ga68-PSMA. The sensitivity of Ga68-PSMA response with biochemical response was 66.7% with 95% CI ranging between 46 %- 82.7%. Ga68-PSMA response did not correlate with biochemical response. Conclusion: Ga68-PSMA has good sensitivity for diagnosis, staging, restaging, evaluation of therapy response and prognostication in prostate cancer.

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Metastatic tumor is one of several etiologies of space-occupying masses in the orbit that accounts for 1-13% of all orbital masses. In the adult patient population, breast cancer is the most common tumor to metastasize to the orbit, followed by metastasis from the lung, prostate, and gastrointestinal tract. Carcinoid tumors are rare neuroendocrine neoplasms derived from enterochromaffin cells, which are found primarily in the gastrointestinal tract and bronchial tree. Liver metastases are the classic presentation of distant disease. Although rare, metastatic carcinoid to the extraocular muscles (EOMs) has been relatively well described in both retrospective case reports and clinical series in the ophthalmology literature, but not in nuclear medicine. Positron emission tomography/computed tomography (PET/CT) using Ga-68-labeled somatostatin-analogues have shown superiority over other modalities for imaging of Neuroendocrine tumor We describe a case of bilateral EOM metastasis from carcinoid lung in Ga-68 DOTANOC PET/CT and treatment with Lu -177 DOTATATE.

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PSMA PET is increasingly being used in imaging of recurrent prostate carcinoma. A case with suspected recurrent Prostate carcinoma (PCa), raised PSA (Prostate specific antigen) and suspected spinal metastases was referred for whole body Ga-68-PSMA PET/MRI. The study revealed PSMA avid recurrent prostate mass and extensive osseous metastases. Abnormal PSMA uptake in the thyroid gland prompted USG-guided FNAC which revealed Hurthle cell neoplasm. Histopathological examination (HPE) of excised gland showed multiple Hurthle cell adenomas in both lobes of thyroid along with foci of papillary thyroid carcinoma which on immunohistochemistry were thyroglobulin positive and PSA negative.

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Dermatomyositis is an inflammatory myopathy with the characteristic features of skin rash and myopathy. We here present a known case of dermatomyositis evaluated with ¹⁸F-FDG PET/CT for the presence of any occult malignancy. The scan was negative for the presence of any malignancy. However, it revealed multiple intensely FDG avid colonic strictures that were later proven on colonoscopic biopsy to be ulcerative colitis. Also, a well-known association of bilateral sacroilitis was simultaneously demonstrated on the scan. The present case demonstrates that ¹⁸F-FDG PET/CT imaging can serve as a one-stop shop imaging modality in dermatomyositis by facilitating detection of occult primary if any and by providing insight into other rare systemic associations.

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Bleomycin-induced interstitial lung disease is not a rare complication of treatment and may prove to be fatal if not suspected early in its course. As FDG PET-CT has become an essential clinical tool for interim and end-of-treatment response assessment in oncology, it is important that radiologists/nuclear medicine specialists be aware of the features of this potentially treatable condition so that treatment can be instigated during an early reversible phase before pulmonary damage has occurred. Herein, we report two cases of bleomycin toxicity featuring different patterns on the treatment-response assessment FDG PET-CT scan.

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Fibrous dysplasia (FD) of the bone is characterized by the medullary cavity of bones becoming filled with fibrous tissue, and its etiology remains unknown. It is usually asymptomatic and found incidentally on imaging studies that are performed for other purposes. FD may closely mimic the appearance of bony metastatic disease on radiological examinations.We report the case of a 45-year-old female patient, which appeared to have multiple bone lesions on initial workup images.Subsequently, the bone lesions that showed increased FDG uptake on PET/CT in right femur and tibia were identified as FD. The present case is a useful addition to the current body of literature of false positive F-18 FDG PET/CT due to a benign skeletal pathology and underscores the importance of high index of suspicion and careful correlation, whenever one comes across such an unusual PET/CT finding.

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20 year old post renal transplant patient developed recurrent episodes of seizure. MRI revealed focal lesion in right parieto-occipital lobe with perilesional edema. FDG PET-CT revealed multiple hypermetabolic lesions in bilateral cerebral hemisphere. Subsequent biopsy from the lesion demonstrated bradyzoites of Toxoplasma gondii with inflammatory cells and thereby, a confirmatory diagnosis of cerebral toxoplasmosis was made. This case demonstrates the fact that increased FDG uptake in cerebral lesions in post transplant patient should be interpreted with caution and confirmed with histopathological correlation.

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Peritoneal lymphomatosis is seen less frequently, but when seen, it is mostly associated with aggressive variants of malignancies. FDG uptake has been reported in peritoneal lymphomatosis both in DLBCL and Burkitt's lymphoma. We report a case of Burkitt's lymphoma with involvement of entire peritoneum, which looks like a “peritoneal super scan” on FDG PET-CT.

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Primary cardiac tumors are rare with angiosarcoma being the most common among malignant cardiac tumor. We present a case of 30-year-old female patient in whom F-18-fluorodeoxyglucose positron emission tomography/computed tomography demonstrated a necrotic mass in right atrium with multiple fluorodeoxyglucose avid lesions in both upper and lower alveolus, liver, multiple bones, and bilateral lungs. Patient underwent biopsy from gum swelling which revealed metastatic angiosarcoma.

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Context: The differential cortical function obtained by Tc-99m EC is comparable to that of Tc-99m DMSA. However, identification of scars on Tc-99m EC images needs to be studied. Aims: The aim of the study is to evaluate role of Tc-99m EC for detection of scarring and differential cortical function by comparing with Tc-99m DMSA. Settings and Design: Prospective observational study of recurrent UTI; minimum 6 weeks after acute episode; when urine examination is negative for pus cells. Materials and Methods: Forty-seven children with normal positioned kidneys underwent Tc-99m EC and DMSA scintigraphy. The DRF and cortical phase images of both studies in the same image matrix size were evaluated by two independent observers for scarring; Tc-99m DMSA was considered as the gold standard. Statistical analysis used: MS Excel 2007 and GraphPad Instat V3.1 and ROC analysis. Results: There was no significant difference in the detection of scarring using two studies with Cohen’s kappa coefficient (κ) 0.932. The sensitivity and specificity of Tc-99m EC for detection of scarring was 98.75% and 99.15%, respectively. There was good agreement between the differential cortical function calculated using two studies. Conclusions: The summed Tc-99m EC images with an acceptable high image contrast allow detection of cortical scarring in patients with normal kidney positions. It is an excellent single-modality comprehensive investigational agent for renal parenchymal defects, function, and excretion evaluation with the added advantages of lower cost, convenience, and low radiation exposure to the child.

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Lung cancer is currently one of the most common malignancies in the world. Metastatic disease is observed in ~ 40% of patients with lung cancer, with the most common sites of metastasis being the bone, liver, brain and adrenal glands. Peritoneal carcinomatosis (PC) is defined as the progression of the primary cancer to the peritoneum. PC is a rare clinical event in lung cancer. Tyrosine kinase inhibitors targeting the epidermal growth factor receptor (EGFR), such as erlotinib are used for the treatment of patients with advanced non-small cell lung cancer (NSCLC). F-18 FDG PET/CT has proven capable of predicting response to therapy with erlotinib. We present a rare F-18 FDG PET/CT image findings of a 45 year old male with NSCLC with PC treated with erlotinib showing response to the treatment.

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Brown tumors seen in hyperparathyroidism are rare, non-neoplastic lesions because of abnormal bone metabolism, and they can mimic benign bone tumors or malignancy. Although biopsy is considered as the gold standard for diagnosis, it can be inconclusive. As the diagnosis of brown tumors is often challenging, a high index of suspicion is essential for diagnosis. We present a case of 21-year-old woman who presented with multiple painful bony lesions, which were initially misdiagnosed as fibrous dysplasia. Due to persistent bone pain and deterioration in her physical mobility, she was referred to tertiary care centre. After thorough clinical workup, she underwent Tc-99m methylene diphosphonate bone scintigraphy that raised strong clinical suspicion of hyperparathyroidism and brown tumors. Subsequently, Tc-99m-methoxy isobutyl isonitrile (MIBI) parathyroid scintigraphy revealed a solitary MIBI avid focal lesion, suggestive of left inferior parathyroid adenoma. Later parathyroidectomy was performed and histopathological examination confirmed it as atypical parathyroid adenoma.

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An area of increased activity in segment IV of liver (quadrate lobe) on ^99mTc-sulfur colloid (TSC) scans has been well documented in patients with superior vena cava obstruction. Similarly intense enhancement of the quadrate lobe in the arterial phase may be seen on computed tomography in patients of superior vena cava syndrome. We present this imaging finding in a case of malignant thymoma causing superior vena cava syndrome and discuss the physiological cause and importance of this sign.

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Central nervous system involvement is a rare manifestation of Langerhans cell histiocytosis (LCH), with bone and skin lesions being more frequent. MR remains the investigation of choice for localizing brain lesions. However, due to poor sensitivity of MRI in detecting osseous and pulmonary lesions, it is not used routinely in staging purposes until and unless indicated. We hereby discuss a case of 6-year-old boy of LCH who was referred for 18-F-FDG PET/CT for staging and knowing the extent of the disease, but a lesion in hypothalamus was picked up incidentally on FDG PET-CT study that was confirmed by MRI.

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Purpose of the Study: With rapid development in the field of nuclear medicine therapy, radiation safety of the personnel involved in synthesis of radiopharmaceuticals has become imperative. Few studies have been done on estimating the radiation exposure of personnel involved in the radio labeling of ¹⁷⁷Lu-compounds in western countries. However, data from the Indian subcontinent are limited. We have estimated whole body radiation exposure to the radiopharmacist involved in the labeling of: ¹⁷⁷Lu-DOTATATE, ¹⁷⁷Lu-PSMA-617, and ¹⁷⁷Lu-EDTMP. Materials and Methods: Background radiation was measured by keeping a pocket dosimeter around the workbench when no radioactive work was conducted. The same pocket dosimeter was given to the radiopharmacist performing the labeling of ¹⁷⁷Lu-compounds. All radiopharmaceuticals were synthesized by the same radiopharmacist with 3, 1 and 3 year experience, respectively, in radiolabeling the above compounds. Results: One Curie (1 Ci) of ¹⁷⁷Lu was received fortnightly by our department. Data were collected for 12 syntheses of ¹⁷⁷Lu-DOTATATE, 8 syntheses of ¹⁷⁷Lu-PSMA-617, and 3 syntheses of ¹⁷⁷Lu-EDTMP. Mean time required to complete the synthesis was 0.81, 0.65, and 0.58 h, respectively. Mean whole body radiation exposure was 0.023 ± 0.01 mSv, 0.01 ± 0.002 mSv, and 0.002 ± 0.0006 mSv, respectively. Overall mean radiation dose for all the three ¹⁷⁷Lu-compounds was 0.014 mSv. Highest exposure was obtained during the synthesis of ¹⁷⁷Lu-DOTATATE. Conclusion: Our data suggest that the manual radiolabeling of ¹⁷⁷Lu compounds is safe, and the whole body radiation exposure to the involved personnel is well within prescribed limits.

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We report a case of a 56-year-old woman diagnosed with infiltrating ductal carcinoma of the left breast, who had undergone left modified radical mastectomy followed by radiotherapy and adjuvant chemotherapy. FDG PET-CT showed metastatic brachial plexopathy with intra-spinal and extra-axial brain metastasis. Metastatic brachial plexopathy along with brain and spinal metastasis is a rare condition with very less incidence. The scan also showed left para-sternal anterior chest wall recurrence with antero-superior mediastinal metastasis.18FDG-PET scanning is a useful tool in evaluation of patients with suspected metastatic plexopathy. It may also be useful in distinguishing between radiation-induced and metastatic plexopathy. Typical pattern of FDG uptake and dual time point imaging may increase specificity and require further evaluation.

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A 44-year-old female with known primary myelofibrosis presented with shortness of breath. High Resolution Computed Tomography thorax revealed large heterogeneously enhancing extraparenchymal soft tissue density mass involving bilateral lung fields. F-18-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography revealed mildly FDG avid soft tissue density mass with specks of calcification involving bilateral lung fields, liver, and spleen. Subsequent histopathologic evaluation from the right lung mass was suggestive of extramedullary hematopoesis.

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A 21 year old male who presented with painful enlargement of both the breasts and a hyperestrogenic state, was found to harbor a heterogeneous mass arising from the right adrenal on contrast enhanced Computed Tomography abdomen. The mass was hypermetabolic with no regional, nodal or distant metastases on Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography /Computed Tomography examination. Notably, substantial tracer uptake was seen in bilateral gynecomastia. The patient underwent a right adrenalectomy with the histopathology report confirming adrenocortical carcinoma. This case demonstrates utility of FDG PET/CT in adrenocortical carcinoma. However, when interpreting FDG PET/CT as a staging tool in oncological male patients, one should consider gynecomastia as a possible cause for increased FDG uptake in the breast as it may lead to a false positive interpretation.

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Hypercalcemia is a common life-threatening complication associated with several malignancies. Parathyroid-related peptide has been shown to cause hypercalcemia in several solid tumors but rarely in penile cancer. We report a case of penile cancer with hypercalcemia causing metastatic visceral calcification in lungs, liver, and stomach detected on bone scan without significant abnormalities on CT scan.

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Germ cell tumors (GCT) account for the 95% of the malignancies associated with testes. They are the most common solid malignancies affecting the males in the age group of 15–35 years. It is known to be bilateral in 3% of cases. We herein present FDG PET-CT findings of a case with biopsy proven GCT with multiple lymph nodal and splenic metastases mimicking lymphomatous neoplasm.

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Introduction: Evidence supporting the use of Sentinel node biopsy (SNB) for nodal staging of early oral squamous cell carcinomas (OSCC) appears to be very promising. Pre-operative lymphatic mapping using planar lymphoscinitigraphy (PL) with or without SPECT/CT in the SNB procedure is useful in sentinel node localization and for planning appropriate surgery. Recently, a large prospective multi-centric study evaluating SNB in cutaneous melanoma, breast and pelvic malignancies, demonstrated that adding SPECT to PL leads to surgical adjustments in a considerable number of patients. Our aim of this study was to evaluate the incremental value of additional SPECT/CT over PL alone in SNB for OSCC. Materials and Methods: This was a retrospective analysis of 44 patients (40- tongue, 4- buccal mucosa) with T1-T2, clinically N0 oral cavity SCC who underwent sentinel node biopsy procedure. PL and SPECT lymphoscinitigraphy images were compared for pre-operative mapping of sentinel nodes. Results: Using a handheld gamma probe, a total of 179 sentinel nodes were harvested, with a mean of 4.06 per patient. PL revealed 75 hotspots with a mean of 1.70 per patient, and SPECT/CT revealed 92 hotspots with a mean of 2.09 per patient. Additional hotpots were identified in 14 patients on SPECT/CT, which included 4 patients, where PL did not detect any sentinel nodes. Conclusion: Pre-operative SPECT/CT in addition to planar lympho-scinitigraphy in sentinel node biopsies of oral cavity SCC detects more number of sentinel nodes compared to planar imaging alone. The higher sensitivity of SPECT combined with better anatomical localization using diagnostic CT may further improve the precision of SNB procedure.

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Purpose: The detection of abdomino-pelvic tumors embedded in or nearby radioactive urine containing 18F-FDG activity is a challenging task on PET/CT scan. In this study, we propose and validate the suprathreshold stochastic resonance-based image processing method for the detection of these tumors. Methods: The method consists of the addition of noise to the input image, and then thresholding it that creates one frame of intermediate image. One hundred such frames were generated and averaged to get the final image. The method was implemented using MATLAB R2013b on a personal computer. Noisy image was generated using random Poisson variates corresponding to each pixel of the input image. In order to verify the method, 30 sets of pre-diuretic and its corresponding post-diuretic PET/CT scan images (25 tumor images and 5 control images with no tumor) were included. For each sets of pre-diuretic image (input image), 26 images (at threshold values equal to mean counts multiplied by a constant factor ranging from 1.0 to 2.6 with increment step of 0.1) were created and visually inspected, and the image that most closely matched with the gold standard (corresponding post-diuretic image) was selected as the final output image. These images were further evaluated by two nuclear medicine physicians. Results: In 22 out of 25 images, tumor was successfully detected. In five control images, no false positives were reported. Thus, the empirical probability of detection of abdomino-pelvic tumors evaluates to 0.88. Conclusion: The proposed method was able to detect abdomino-pelvic tumors on pre-diuretic PET/CT scan with a high probability of success and no false positives.

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