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Abstract: A 34-year-old woman who presented with severe psychosis and clinical features of Cushing syndrome underwent 18 F-FDG PET/CT that revealed hypermetabolic lung lesion along with predominantly increased metabolism of bilateral basal ganglia, a scintigraphic correlate of acute psychosis. The lesion was surgically excised and histopathologically proven to be adrenocorticotropic hormone-producing lung carcinoid. Posttreatment 18 F-FDG PET scan showed restoration of normal brain metabolism with complete reversal of psychosis. Even though rare, one should be aware of psychosis as an initial presentation of Cushing syndrome and use of 18 F-FDG PET/CT for mapping brain metabolism as shown in this case., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Sella turcica and petrous bone metastasis from differentiated thyroid carcinoma are rare clinical entities, with only a few limited cases reported to date. Two cases, one of sella turcica metastasis and the other of petrous bone metastasis from carcinoma of the thyroid gland, are presented. The cases diagnosed to have arisen from poorly differentiated thyroid carcinoma and follicular carcinoma of thyroid, respectively, subsequently underwent total thyroidectomy, radioiodine (RAI) scans and RAI therapies with iodine-131, external radiotherapy, and levothyroxine suppression with follow-up. Their clinical symptoms gradually subsided, with reduction in serum thyroglobulin, and finally resulted in disease stabilization. With the multimodality therapeutic approach, both patients are alive to date, with 48- and 60-month survival post diagnosis, respectively., Competing Interests: Conflict of Interest None., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. ( https://creativecommons.org/licenses/by/4.0/ ).)

Pharmaceutical grade 3'-deoxy-3'-[ 18 F]fluorothymidine [ 18 F]FLT was synthesized using 3-N-Boc-5'-O-dimethoxytrityl-3'-O-nosyl-thymidine (BOC-Nosyl) precursor, in the general purpose TRACERlab FX modules. Purification of [ 18 F]FLT, via solid phase extraction (SPE) after radiosynthesis, using a combination of different SPE cartridges, yielded satisfactory results, with radiochemical and chemical purity >99%. While the non-decay corrected radiochemical yield (RCY) with 20 mg (24 μmole) of BOC-Nosyl precursor was found to be 6.80 ± 0.16%, the decay corrected radiochemical yield (RCY) was 9.95 ± 0.24%. Residual acetone, acetonitrile, and ethanol levels were found to be 22.97 ± 0.76, 109.08 ± 0.93, and 7,666.45 ± 3.7 ppm, respectively. A simplified method for solid-phase purification of [ 18 F]FLT was developed, circumventing the need for HPLC purification. Biodistribution in C57BL/6 mice with B16F10 cell line-induced melanoma showed tumor to blood ratio of ~3.8 at 90 min. PET/CT imaging of normal rabbit injected with [ 18 F]FLT shows selective uptake in the bone marrow and small intestine. [ 18 F]FLT was found to be excreted through the kidneys and get collected in the urinary bladder, 120 min post injection. PET/CT imaging performed in rabbit model at 30, 60, 90, and 120 min post [ 18 F]FLT injections showed concordance with tissue distribution kinetics of mice tumor model., (© 2022 John Wiley & Sons, Ltd.)

Background: Individuals with suicidal behaviours are increasingly recognized as having impairments in brain metabolism. However, these are not well delineated., Aim: To evaluate regional cerebral glucose metabolism (rCMglu) in subjects with suicidal behaviours and assess differences in rCMglu between depressed and non-depressed suicidal subjects., Methods: Thirty-three subjects with suicidal behaviours were assessed using Columbia Suicide Severity Rating scale (CSSRS) and Beck's Depression Inventory (BDI). Brain metabolism was assessed using [ 18 F]Fluoro,Deoxy-Glucose Positron Emission Tomography (FDG-PET)., Results: Of 33 subjects, eighteen had depression. FDG-PET findings revealed that in comparison to mean asymptomatic controls, subjects had decreased rCMglu in right inferior frontal, left Broca's, left inferiolateral andsuperiolateral temporal, right inferior parietal and left posterior cingulate cortex. Increased rCMglu was seen in bilateral superior and medial frontal, right inferiolateral and posteriomedial temporal cortex, and midbrain. CSSRS total intensity inversely correlated with rCMglu in medial frontal cortex, left Broca's and superiolateral temporal cortex and directly correlated with rCMglu in right cerebellum. There was no significant difference in rCMglu between depressed and non depressed group., Conclusions: Significant differences exist in rCMglu of suicidal individuals, chiefly in frontal and temporal regions. Understanding these would help us identify individuals more at risk for suicidal behaviours., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Introduction: The quality control parameters of in-house-produced 90 Y-Acetate from high-level liquid waste (HLLW) using supported liquid membrane (SLM) technology were validated and compared with the pharmacopeia standard. The radiolabeling of DOTATATE yielding 90 Y-DOTATATE in acceptable radiochemical purity (RCP), with expected pharmacological behavior in in vivo models, establish the quality of 90 Y-Acetate. Clinical translation of 90 Y-Acetate in formulation of 90 Y-DOTATATE adds support toward its use as clinical-grade radiochemical. Methods: Quality control parameters of 90 Y-Acetate, namely radionuclide purity (RNP), were evaluated using β - spectrometry, γ-spectroscopy, and liquid scintillation counting. RCP and metallic impurities were established using high-performance liquid chromatography and inductively coupled plasma optical emission spectrometry, respectively. The suitability of 90 Y-Acetate as an active pharmaceutical ingredient radiochemical was ascertained by radiolabeling with DOTATATE. In vivo biodistribution of 90 Y-DOTATATE was carried out in nude mice bearing AR42J xenografted tumor. Clinical efficacy of 90 Y-DOTATATE was established after using in patients with large-volume neuroendocrine tumors (NET). Bremsstrahlung imaging was carried out in dual-head gamma camera with a wide energy window setting (100-250 keV). Results: In-house-produced 90 Y-Acetate was clear, colorless, and radioactive concentration (RAC) in the range of 40-50 mCi/mL. RCP was >98%. 90 Sr content was <0.85 μCi/Ci of 90 Y. Gross λ content was <0.8 nCi/Ci of 90 Y and no γ peak was observed. Fe 3+ , Cu 2+ , Zn 2+ , Cd 2+ , and Pb 2+ contents were <1.7 μg/Ci. The radiolabeling yield (RLY) of 90 Y-DOTATATE was >94%, RCP was >98%. The in vitro stability of 90 Y-DOTATATE was up to 72 h postradiolabeling, upon storage at -20°C. Post-therapy (24 h) Bremsstrahlung image of patients with large NET exhibit complete localization of 90 Y-DOTATATE in tumor region. Conclusions: This study demonstrates that the in-house-produced 90 Y-Acetate from HLLW can be used for the formulation of various therapeutic 90 Y-based radiopharmaceuticals. Since 90 Y is an imported radiochemical precursor available at a high cost in India, this study which demonstrates the suitability of indigenously sourced 90 Y, ideally exemplifies the recovery of "wealth from waste." The Clinical Trial Registration number: (P17/FEB/2019).

The efficacy of Lu-DOTATATE in large neuroendocrine tumors (NETs) is reduced because of the lower energy (Eβmax 0.497 MeV) and shorter range of Lu. The pure β-emitter Y with its longer β range is more effective in larger tumors. This should be balanced with the greater risk of Y-DOTATATE-related nephrotoxicity. Sequential duo-peptide receptor radionuclide therapy may result in a better response with minimal adverse effects in large-volume heterogeneous NETs. A 56-year-old man with large rectal NET liver metastases, treated with Y-DOTATATE and Lu-DOTATATE and sequential duo-peptide receptor radionuclide therapy, presented with post-Y-DOTATATE bremsstrahlung and PET/CT in comparison with Ga-DOTATATE PET/CT and Lu-DOTATATE scans.

Background: Few nuclear reactors in the world producing high specific activity (HSA) 99Mo using enriched 235U (HEU), are aging and are planned for shut down in the near future. Further, HEU will not be freely available, due to safeguards, and the technology for 99Mo from low-enriched 235U (LEU) is not yet widely accepted since 239Pu contamination in the product is an issue. Production of 99mTc from low specific activity (LSA) 99Mo obtained from 98Mo(n,)99Mo reaction in research reactor and 100Mo(,n)99Mo reaction in accelerator or directly from 100Mo(p,2n)99mTc nuclear reaction in cyclotron, has been explored [1]. The methyl ethyl ketone (MEK) based solvent extraction technique is n well known method for the separation of 99mTc from low specific activity 99Mo. The 99Mo/99mTc autosolex generator [2], a computer controlled automated module, utilizes the conventional MEK solvent extraction method for extraction of 99mTc. Herein, we have validated the usage of autosolex for preparation of pharmacopoeia grade 99mTcO4- from 7.40-27.5 GBq of LSA 99Mo-SodiumMolybdate (99MoO42-) solution and validated the quality of the 99mTcO4- by preparing wide range of 99mTc-radiopharmaceuticals (99mTc-RP)., Materials and Methods: The 99mTcO4- was extracted from the autosolex as described in [2] starting from 7.40-27.5 GBq of LSA 99MoO42- and subjected to the required physico-chemical and biological quality control (QC) tests. The eluted 99mTcO4- labeled various fourth generation 99mTc radiopharmaceuticals cold kits (99mTc-cold kits) apart from regular 99mTc-cold kits in our centre. Various 99mTc-RP extracted 99mTcO4- using standard procedures [3] were prepared and subjected to required QC as Indian Pharmacopeia monograph [4] and used in scintigraphic imaging in patients. The radiation exposure dose to the operator were compared between autosolex and manual MEK based solvent extraction generator., Results: The extracted 99mTcO4- from autosolex is a clear and colorless solution with pH between 5.0-6.5. The elemental molybdenum (Mo) and aluminum (Al) content <10µg/mL, MEK levels <0.1%, 99Mo breakthrough <0.030% and radiochemical purity (RCP) >98%. All the extracted 99mTcO4- batches complies sterility test, endotoxin limit (EL) <5EU/mL. The RCP of all the labeled 99mTc-RP >95%. The autosolex delivers much less radiation dose to the operator than the convention manually handled MEK based solvent extraction generator., Conclusions: Autosolex Generator was successfully used to obtain pharmaceutical grade 99mTcO4- from LSA 99MoO42- and generator is safe in radiological and pharmacological point of view. The suitability of the autosolex for use in hospital radiopharmacy was shown by using the 99mTcO4- to prepare various 99mTc-RP and using these 99mTc-RP for scintigraphic imaging in patients.

Tumor thrombus is a rare complication of many solid tumors. We present a case of renal cell carcinoma whose baseline contrast-enhanced computerized tomography (CT) revealed an heterogeneously enhancing mass in the upper half of right kidney with tumor thrombus in the right renal vein extending to suprarenal inferior vena cava (IVC), crossing the cavoatrial junction and reaching up to the right atrium (Grade IV). Fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/CT imaging revealed large irregular right renal mass, hypermetabolic tumor thrombus extending from the right renal vein to suprarenal IVC reaching up to the right atrium. There was no FDG uptake noted in the infrarenal IVC and bilateral iliofemoral venous thrombi. Thus, 18F-FDG PET/CT was not only helpful in the staging, but was also helpful in differentiating tumor thrombus from bland thrombus in our patient.

Purpose: To study the (18)F-FDG uptake pattern in brown adipose tissue (BAT) over an extended time period, by multiple-time-point fluorodeoxyglucose positron emission tomography (FDG-PET) imaging. The primary objective for this kind of research was that it could form a basis and may have further implications for obesity research, metabolic diseases and for cachexia of both malignant and benign origin., Methods: A total of 12 patients who had undergone routine FDG-PET for disease evaluation and had demonstrated prominent BAT uptake in their baseline scans were selected. The patients with the diagnosis of neuroendocrine tumors were excluded. Maximum standardized uptake values (SUVmax) were calculated in the BAT of the supraclavicular and paravertebral areas of either side, and were analyzed separately to examine their behavior individually. Time activity curves (TACs) were generated for [A] BAT SUVmax values and [B] SUVmax ratio of BAT/lung (B/L SUVmax ratio) at various time points., Results: Ten out of the 12 patients were imaged at four time points, and two patients were imaged for two time points. Amongst a total of n = 30 sites, 23 were imaged at four time points and seven were imaged at two time points. Seventeen out of 30 area sites (56.67 %) demonstrated a peak value at 60 min and a falling trend of SUVmax afterwards; the remaining showed a peak uptake value between 85 and 300 min after the first scan (i.e. 145-360 min after injection), and falling values thereafter. With regard to the B/L SUVmax ratio, ten out of 30 sites (33.33 %) demonstrated peak uptake at 60 min, and the remaining showed a rise, with peak uptake at times between 85 and 300 min after the first scan (i.e. 145-360 min after injection) and falling values thereafter. No additional area of BAT uptake was observed over the extended time period in this study., Conclusion: Wide variability was observed in the BAT FDG uptake over an extended period of time. Nearly half of the sites demonstrated an increase in FDG uptake until 360 min (i.e. 6 h) after injection, while the remaining half showed peak uptake at 1 h and subsequent fall of uptake. In the future, it will be worthwhile to study whether there exists any difference in time course of FDG uptake in brown fat between patients with cancer and those scanned for benign etiologies, or between obese and non-obese individuals.