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Purpose: Tc-99m Methylene diphosphonate (MDP) is prepared in house by labeling MDP cold kit. Each kit is a single time use vial and contains large amounts of reagent sufficient for preparing multiple doses. Therefore, several centers are adopting the practice of fractionating the MDP kit so that it can be used multiple times. The aim of the study was to evaluate the effect of kit fractionation on radiopharmaceutical property. Materials and Methods: The MDP kit was fractionated using two different approaches, namely, vial and syringe method. The quality of Tc-99m MDP prepared using these approaches was assessed and compared with that prepared by the conventional method. The image quality was evaluated in a total of 100 patients. Results: The vial and syringe fractionated Tc-99m MDP showed >95% RCP till the 4^th and 2^nd days of fractionation, respectively. Percentage radiochemical purity deteriorated to 83.6% and 88% on the 8^th day of fractionation in the vial and syringe method, respectively. No microbial growth was observed in any of these methods till the 8^th day of fractionation. The reconstituted MDP solution during all preparations was clear and colorless in appearance with pH ranging from 6.5 to 7.5. The image contrast, contrast-to-noise, and signal-to-noise ratio were statistically similar in both methods compared to the conventional method until the 2^nd day of fractionation. The image quality data showed no statistical difference among images of vial and syringe fractionated MDP as compared to the conventional unfractionated Tc-99m MDP. Conclusions: The observations revealed that if fractionated with utmost care, both methods yield almost similar results.

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Purpose of the Study: The purpose of the study is to establish the reference values of global and regional gastric emptying parameters (GEPs) using a standard vegetarian meal acceptable to the Indian population and compare the values derived on different camera view methods. Materials and Methods: Thirty-six consecutive healthy subjects with age ≥18 years underwent gastric emptying scintigraphy using anterior, posterior, and left anterior oblique (LAO) views. GEP was derived based on decay corrected counts in regions of interest defined on the whole and proximal stomach. Counts in the anterior and posterior view images were used to derive GEP based on geometric mean (GM) method. Comparison of GEP among different camera view methods was done with Friedman test and post hoc Wilcoxon signed-rank test after Bonferroni correction. Reference values were derived based on percentiles. Results: Rapid gastric emptying based on GM method was defined as percent retention <20% at 1 h while delayed emptying as percent retention >40% and >5% at 2 h and 4 h, respectively. The reference range of half-time of gastric emptying was 23–109 min. The reference value of intragastric meal distribution at time t = 0 was >64%, while the reference range of retention index was 0.7–1.3. Although the overall distribution of GEP derived on different camera view methods could be statistically significant (P < 1.00), the small differences in the derived reference values are likely to be of no clinical significance. Conclusion: The reference values of GEPs established in this study can be generalized for the Indian population and may be applied to aid in clinical decision making. We recommend the GM method as the preferred method, although single view method (LAO preferred over anterior) can also be an acceptable alternative.

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Purpose: We aimed to evaluate the radiation exposure to patients undergoing positron emission tomography/computed tomography (PET/CT)-guided biopsies. Materials and Methods: Patients undergoing PET/CT-guided biopsy were recruited prospectively from October 2019 to April 2020. PET/CT-guided biopsy from a tracer avid site was done using an automated-robotic-arm 1 h after intravenous injection of F-18-fluorodeoxyglucose (FDG) (2-5 mCi) or Ga-68-PSMA (1–4 mCi). Regional CT-images were acquired for biopsy planning and confirmation of needle placement. The internal radiation exposure due to the PET component was estimated using the value of activity injected and dose-coefficient for FDG and PSMA. The external radiation exposure due to the CT component was estimated using the value of dose length product and organ coefficients conversion factor. The total effective dose during the procedure was calculated by adding exposure due to both CT and PET components. Percentage contribution from CT and PET component to total effective dose was compared using a paired t-test. Results: A total of 101 patients (76 males) were recruited for PET/CT-guided biopsy using FDG (n = 79) and PSMA (n = 22). The mean effective-dose due to PET and CT components and total effective-dose was 2.49 ± 1.02 mSv, 2.35 ± 1.03 mSv and 4.83 ± 1.90 mSv, respectively, for FDG-guided procedures and 1.60 ± 0.57 mSv, 3.06 ± 1.36 mSv, and 4.66 ± 1.37 mSv for Ga-68-PSMA-guided procedures. The percentage contribution of PET and CT in total effective-dose was comparable in F-18-FDG and Ga-68-PSMA PET/CT-guided biopsy procedures; however, for Ga-68-PSMA PET/CT-biopsies, CT contributed a higher radiation dose than PET component. Conclusion: PET/CT-guided biopsy is a safe interventional procedure, and radiation exposure to the patients was less than routine whole-body PET/CT-imaging.

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Background: Despite the lymphatic system being so important and extensive, the field of lymphatic diseases, research is still very young. Lymphedema is a progressively debilitating condition with no known “cure.” Specific pathologies that could benefit from improved lymphatic drainage by advanced super surgical techniques or engineered tissue transfer are being sought. Microsurgical techniques like lymphovenous bypass and anastomosis have spurred interest as they tend to physiologically restore the damaged lymphatic channels and may be a key to permanent cure. The latest in the field is vascularized lymph node transfer (VLNT), indicated in post mastectomy or other post operative settings producing disruption of regional lymphatic channels and draining lymph nodes. Autologous healthy lymph nodes are transferred along with surrounding fat and vascular pedicle to the affected limb in a bid to promote lymphangiogenesis. Lymphoscintigraphy (LS) is a simple, noninvasive nuclear technique used in identifying upper or lower limb lymphatic dysfunction and obstruction with a high degree of sensitivity. Quantitative LS is extremely useful in follow-up assessment of lymphedema postmanual lymphatic drainage (MLD) or other forms of medical management. Aim: We hypothesize that LS can document perinodal lymphangiogenesis post VLNT. Material and Methods: Three cases of acquired lymphedema (suspected filariasis and postmastectomy conditions) who underwent VLNT in our institute were prospectively studied with LS. The imaging findings highlight the subtle lymphatic regeneration along with the vascularized graft in all three patients during the early postoperative period. Conclusion: This is the first (pilot) study documenting early spontaneous perinodal lymphangiogenesis after VLNT in human subjects. ^99mTc Nanocolloid LS has been found to be incremental in demonstrating early lymphangiogenesis.

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Purpose of Study: Aim of the study was to evaluate the role of ⁶⁸Gallium-DOTANOC positron emission tomography/computed tomography (⁶⁸Ga-DOTANOC PET/CT), a pan somatostatin receptor (SSTR) analog in the clinical management of patients with neuroendocrine tumors (NETs) and its correlation with conventional imaging. Materials and Methods: We retrospectively evaluated 69 patients of known/suspected NETs who underwent ⁶⁸Ga-DOTANOC PET/CT scan for tumor localization (n = 15), stage modification (primary staging, n = 26 and restaging, n = 25) and therapy monitoring (n = 3). We also compared PET scan with conventional imaging as reference standard and evaluated the impact of PET/CT in the clinical management of patients. Results: The concordant findings on ⁶⁸Ga-DOTANOC PET/CT and conventional imaging seen in 33 and discordant in 36 patients. Among discordant group, disease was upstaged in 32 patients; down staged in 3 patients; no stage change in one patient. PET/CT localized primary tumor in 4 patients. Among patients with raised tumor markers (39/69), PET was positive in 29 and negative in 10 patients. Patients were followed for mean duration of 27 months to assess management. We found strong agreement between positive PET and raised tumor markers (Kappa value = 0.8). Sensitivity and specificity of PET/CT for primary tumor localization, stage modification, and therapy monitoring was >90% (P < 0.05). Conclusions: Study shows that DOTANOC, a broad spectrum SSTRs binding peptide labeled with Ga-68 in PET/CT scan is an excellent modality in the management of NETs patients.

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Aims: The production of nitrogen-13 (¹³N)-NH₃ by ethanol method using automated synthesizer and accessing the production yield, quality control for clinical application. Context: ¹³N, together with ¹⁸F, ¹⁵O, and ¹¹C, is one of the positron emitters that can be produced on the multi-gigabecquerel scale in biomedical cyclotrons. (¹³N)-ammonia is frequently used for cardiac PET studies. It is widely applied for the evaluation of myocardial perfusion in the clinical assessment of cardiac disorders. Simple, fast, and reliable preparation methods have contributed to the routine application of this tracer. Although only two methods are available, a challenge remains to adopt a more efficient and consistent approach to its production. For clinical application, routine production of this tracer is mandatory in compliance with regulatory guidelines. Being at hospital radiopharmacy it is our responsibility to support the clinical service with uninterrupted production and supply of (¹³N)-NH₃. Materials and Methods: The chemicals were used commercially available from Sigma Aldrich, India, Ltd., and Fisher Scientific, India, Ltd. (Mumbai, India), Sep-Pak CM cartridges (Waters India, Pvt., Ltd.,). Radio-thin layer chromatography was carried out using aluminum sheets precoated with silica gel 60 F254 (E. Merck, India). Results: The protocol developed with MPS-100 synthesizer yield (¹³N)-NH₃ 95–97% (EOB) with a synthesis time of around 7 min. Conclusions: With the installation of HM-18 cyclotron at our hospital, center is capable to produce (¹³N)-NH₃ of good yield and purity through the ethanol method, for mycocardial perfusion studies. Our protocol is simple, reproducible, and robust.

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Background: The aim of this study was to determine the advantages of preoperative sentinel lymph node mapping (SLNM) by single photon emission computed tomography/computed tomography (SPECT / CT) in patients with early-stage cutaneous head-and-neck malignancies. Materials and Methods: We conduct a 7-year and 6 months retrospective, cross-sectional study. Patients with early-stage malignant head-and-neck skin tumors and cutaneous adnexa who underwent SLNM by SPECT/CT from March 2012 and December 2019, were included in the study. Results: We retrospectively analyzed 28 patients: Melanoma was the most frequent tumor (64.2%), followed by squamous cell carcinoma (25%). The anterior cheek was the most common functional subsite (25%). Twenty-seven patients (96.4%) had a successful SLN detection with SPECT/CT. Neck lymph node dissection was performed in 23 patients (82.1%). According to the pathological specimen, lymph nodes were found in all of them; hence, the efficacy of the SPECT/CT for SLNM was 100%. At 7-year follow-up, systemic recurrence was found in one patient (3.6%), another had locoregional recurrence (3.6%), and the mortality rate was 3.6%. Conclusions: In early-stage malignant head-and-neck skin tumors, there is a high concordance between SLN found by SPECT/CT and the histopathological results. Preoperative SPECT/CT accurately detects the SLN, assesses unexpected lymph nodes and their drainage pathways, and facilitates their location by reliably showing the relationships between sentinel nodes and important anatomic structures. This allows to perform a clear preoperative evaluation, an accurate staging for all patients and to avoid excessive dissections that could result in cosmetic and functional deformities.

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Tumor-induced osteomalacia (TIO) is a rare cause of severe debilitating osteomalacia, due to hypophosphatemia. A strong clinical suspicion based on biochemical parameters can lead to the search for a culprit tumor in the body. The disease entity is more commonly caused by benign mesenchymal tumors. While many imaging modalities have been tried, it is now known that these tumors show high somatostatin receptor (SSTR) expression. Hence SSTR receptor imaging has emerged as a useful diagnostic tool. Here we present a series of TIO cases with clinical presentation and imaging characteristics.

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Langerhans cell histiocytosis (LCH), also known as histiocytosis X, is a rare systemic disorder arising from clonal proliferation of immature CD207-positive (langerin) myeloid dendritic cells (histiocytes) in the skin and visceral organs with a tendency to involve single or multiple organ systems with variable clinical course and prognosis. The incidence of LCH is very less in adult and occurs almost exclusively in children. Genital, perianal, and lung lesions are considered to be rare manifestations of adult LCH. We describe a case of 31-year-old, nonsmoker female who presented in February 2020 with itching and burning sensation in perianal and vulvar regions accompanied with multiple nonhealing ulcers and papillomatous lesions. These lesions gradually increased in size with no response to antibiotics and topical steroids. She was advised positron-emission tomography–computed tomography (PET-CT) scan for further evaluation. After PET-CT scan, her provisional diagnosis of multisystem, multifocal Langerhans cell histiocytosis with high-risk organ involvement was made. Both vulvar and perianal lesions were biopsied which was suggestive of Letterer–Siwe variant of LCH. The prognosis of this variant is very poor even with aggressive chemotherapy and 5-year survival rate of only 50%. Hence, it requires careful consideration during diagnosis and management.

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Objective: The aim of the present study was to design and evaluate two MeVisLab networks, one for co-registration of positron emission tomography/computed tomography (PET/CT) images and second for cropping the co-registered PET/CT images. Materials and Methods: Two MeVisLab networks, one to co-register and export PET/CT DICOM images and second for cropping the co-registered PET/CT images were designed using different modules of registration toolkit MERIT. One hundred and twenty-five PET/CT studies were exported from Siemens and GE scanners in DICOM format. These images were co-registered and cropped with our designed networks. The images co-registered with our network were compared visually with the co-registered images of same PET/CT studies on vendor provided workstations by an experienced nuclear medicine physician (NMP). The perfection of the cropping of co-registered images was also assessed visually. Results: Visually, NMP found all 125 images co-registered using the network designed in our study similar to the co-registered images of vendor provided workstations. Furthermore, the cropping of all co-registered images was perfectly done by our network. Conclusion: Two MeVisLab networks designed and evaluated in the present study can be used for co-registration of PET/CT DICOM images and cropping the co-registered PET/CT images.

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Lymphomas are common solid malignancies. They are associated with substantial morbidity and mortality. Hodgkin's lymphoma (HL) and Non-HL (NHL) are subtypes of lymphoma. Lymph nodes are the most common site of involvement, though practically any organ may be involved. NHL has preponderance for extranodal involvement. Primary uterine and ovarian NHL is scarce. However, in advanced systemic disease, secondary utero-ovarian involvement may be seen. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) is a pivotal imaging modality in lymphomas. It abets in pretreatment staging, posttherapy restaging, and surveillance. We present three stage-IV NHL cases with secondary utero-ovarian involvement. FDG PET/CT as a baseline imaging modality established the disease burden and organ involvement.

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Osteogenic osteosarcoma is an aggressive malignant bone tumor with the tendency for local invasion and early metastases. Radionuclide bone scans play an important role in disease management by identifying other areas of skeletal involvement as well as extraosseous metastases. Osteogenic sarcoma metastasis is known to accumulate bone-avid agents due to their osteogenic potential. Here, we report a case of osteogenic osteosarcoma of distal femur with the absence of pleural effusion but extensive extraosseous areas of metastatic involvement in distant lymph nodes, subcutaneous planes (in the form of nodules), abdominal wall, multiple intraperitoneal deposits, breast, and bone metastases visualized on preoperative Tc-99 m methylene diphosphonate bone scan.

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Skeletal metastases of unknown primary represent skeletal metastases where primary tumors remain obscure. They usually arise from lung and prostate cancer. We present a case of a young male who presented with severe bone pains, weight loss, and generalized weakness. Fludeoxyglucose positron emission tomography–computed tomography reveals extensive skeletal metastases, a mass in the pancreas tail, and other metastatic lesions. He had no liver or lung metastases. This case presents a rare presentation of carcinoma pancreas.

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We present a case of Anti-IgLON 5 encephalitis with Lewy body dementia. ¹⁸F fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) scan and 99 mTc-TRODAT-1 SPECT/CT scan were done. 99 mTc-TRODAT-1 scan findings revealed severely reduced concentration of dopamine transporter in bilateral basal ganglia, suggestive of a degenerative parkinsonian disorder. 18F-FDG PET scan findings were suggestive of moderate-to-severe hypometabolism in the bilateral parieto-temporal and bilateral occipital cortices including the primary visual cortices, supporting Lewy body spectrum disease with associated hypermetabolism in the bilateral sensorimotor cortices, bilateral basal ganglia, thalami, brain stem, and bilateral cerebellar hemispheres suggestive of inflammatory pathology.

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Bladder cancer (BC) is among the top ten most common cancer types globally. Muscle invasive BC has a high incidence of metastasis. Metastatic BC has a poor prognosis and limited treatment options. Here, we present a middle-aged man with oligometastatic BC, which was treated with palliative chemotherapy. He had significant clinical improvement. However, interim 18F-Fluorodeoxyglucose positron emission tomography/computed tomography demonstrates a rapid disease progression extensive metastasis.

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Purpose: The comparison of angiogenesis imaging (Ga-68-DOTA-Arginine-Glycine-Aspartic Acid [RGD]) positron emission tomography/computed tomography [PET/CT]) with metabolic imaging (F-18 fluorodeoxyglucose [FDG] PET/CT) in primary staging and response assessment to neoadjuvant chemotherapy (NACT) in locally advanced breast cancer (LABC) patients. Methods: In this prospective study, 85 female patients with LABC were subjected to two PET/CT studies (Ga-68-DOTA-RGD₂ and F-18 FDG) within 1 week of each other. Thirty patients had repeat studies 4 weeks after completing eight cycles of NACT. Response assessment was done by RECIST 1.1 criteria. Results: Ga-68-DOTA-RGD₂ and F-18 FDG uptake in the primary tumor were seen in all patients. Ipsilateral axillary and internal mammary lymph nodes were detected in 77 (90.5%) versus 80 (94.1%) and 22 (25.8%) versus 27 (31.7%) patients on Ga-68-DOTA-RGD₂ and F-18 FDG scans, respectively. Ipsilateral supra-clavicular lymph nodes and skeletal lesions were noted in 17 (20%) versus 21 (24.7%) patients and 23 (27.0%) versus 24 (28.2%) patients on Ga-68-DOTA-RGD₂ versus F-18 FDG studies, respectively. However, the Ga-68-DOTA-RGD₂ did not show uptake in F-18 FDG avid liver lesions (LLs) in 10 patients, adrenal lesion in one patient, mediastinal lymph nodes in 2 patients, lung nodules, and pleural soft-tissue deposits, each in one patient. In response assessment, 23 and 25 patients had concordance with RECIST1.1 criteria on F-18 FDG and Ga-68-DOTA-RGD₂ scans, respectively. However, there were discordant results in four patients on Ga-68-DOTA-RGD₂ scan and two patients on F-18 FDG scans. Conclusion: Metabolic imaging is better in primary staging and chemotherapy response assessment than angiogenesis imaging in LABC patients. The latter may miss the metastatic soft-tissue deposits, adrenal, and LLs.

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Benign metastasizing leiomyoma is a rare condition where benign smooth muscle tumors having a histological appearance similar to uterine leiomyoma are present at distant sites. This entity is commonly associated with a past history of hysterectomy done for uterine fibroids. The knowledge of the presence of significant fluorodeoxyglucose uptake in leiomyoma helped in the diagnosis of this condition in a 47-year-old patient who being evaluated for multiple unusual sites of metastases; this was further confirmed on histopathology.

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Allogenic bone is the most commonly grafted tissue which provides only osteoconductive property, in which it acts as a scaffold to facilitate the ingrowth of the vessels and migration of host cells capable of osteogenesis. It can be used as a substitute for autografts as the latter is associated with morbidity and limited donor site availability. Its applications are expanding in all aspects of orthopedic surgery, notably in revision hip replacement or surgical treatment for bone tumors or benign conditions. The balance between osteolysis and osteogenesis must be maintained for graft incorporation to occur and thus postoperative imaging is essential for differentiation between grafts and recurrent disease or viability/nonviability. Here, we present three cases, in which bone allografting was done who underwent serial 99 mTc-methylene diphosphonate three-phase bone scintigraphy with single-photon emission computed tomography/computed tomography to assess the viability, integrity, and the incorporation of the graft.

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¹³¹I is widely used for the treatment of goiter and residual and metastatic thyroid cancer. Uptake of ¹³¹I is mainly due to the expression of sodium-iodide symporter in the target tissues. Incidental third space accumulation in the pleural and pericardial cavity can be encountered due to passive diffusion of tracer into these cavities. We present an interesting finding of ¹³¹I accumulation in the scrotal hydrocele in a 70-year-old patient with a metastatic classical variant of papillary thyroid carcinoma, who was treated with 200 m Ci of ¹³¹I.

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Brain metastasis originating in adenocarcinoma of the prostate is rare and can be expected in cases of disseminated bone and soft-tissue disease. Asymptomatic brain metastasis is rare at any point of the disease stage. Ga-68 PSMA positron emission tomography-computed tomography (PET-CT) is one of the useful investigations for assessing the disease status in adenocarcinoma of the prostate. We report a case of asymptomatic brain metastases detected in Ga-68 PSMA PET-CT scan.

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Calcinosis of soft tissue is a rare but known complication of dermatomyositis (DM), mostly associated with juvenile DM and rare in adult DM. Bone scan with Tc-99m Methylene diphosphonate is useful in disease mapping and has high sensitivity to know the extent of calcinosis. However, there is scanty literature available on the utility of bone scan in treatment response evaluation in DM. Rituximab has been found useful in adult DM with calcinosis unresponsive to conventional treatment. We describe an interesting case showing partial response to rituximab on bone scan with single-photon emission tomography-computed tomography.

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Pulmonary sclerosing pneumocytoma is an exceedingly rare neoplasm of the lung. These tumors are usually slow growing with a benign disease course but can easily be mistaken for carcinoid tumors or adenocarcinoma in cytology or histopathology specimens. Rare occurrences of metastases have been reported in the literature making ¹⁸F-labeled fluoro-2-deoxyglucose positron emission tomography and computed tomography useful for the evaluation of these tumors.

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