Differentiated thyroid cancer (DTC) is primarily evaluated using radioiodine (RAI) scanning; however, this approach is limited by the suboptimal imaging properties of 131I, the cost and limited availability of 123I, and restricted access to 124I. [18F]Tetrafluoroborate (TFB), a PET radiotracer targeting the sodium/iodide symporter, has emerged as a promising alternative. This prospective study assessed the diagnostic performance and biodistribution of TFB PET compared with 131I scintigraphy in patients with DTC. This prospective study enrolled 58 patients with histopathologically confirmed DTC after total or near-total thyroidectomy. Forty-eight patients underwent both TFB PET/CT and 131I SPECT scintigraphy, while 10 underwent only TFB PET for biodistribution analysis. Patients were stratified into preradioiodine (TFB before 131I; n = 28) and postradioiodine (TFB after 131I; n = 20) subgroups based on recent radioiodine administration (either diagnostic or therapeutic) to evaluate the potential stunning effect of 131I on TFB uptake. Patient- and lesion-based analyses were performed, and agreement was assessed using Cohen’s kappa. In patient-based analysis, concordance between modalities showed both TFB and 131I positivity in 20 patients, TFB-only positivity in 1 patient, 131I-only positivity in 5 patients, and negativity in both modalities in 22 patients, yielding substantial overall agreement (κ = 0.75). Agreement was almost perfect in the preradioiodine group (κ = 0.84) but declined to a moderate level in the postradioiodine group (κ = 0.49). In lesion-based analysis (n = 56), overall detection rates were comparable (TFB, 85.7

Lutetium-177 (177Lu)-labeled radiopharmaceuticals are widely used in targeted radionuclide therapy, and radiochemical purity (RCP) is a critical quality parameter for clinical application. This study retrospectively evaluated the long-term quality control performance of 177Lu-labeled radiopharmaceuticals prepared using a fully manual labeling approach without automated synthesis modules between 2010 and 2026 at a single center. A total of 1815 productions, including [177Lu]Lu-DOTATATE, [177Lu]Lu-PSMA-617, [177Lu]Lu-DOTANOC, [177Lu]Lu-FAPI-04, and [177Lu]Lu-EDTMP, were analyzed, corresponding to 3330 clinical administrations. Radiochemical purity was routinely assessed by high-performance liquid chromatography (HPLC) and instant thin-layer chromatography (ITLC). Detailed statistical evaluation was performed on randomly selected high-volume groups and all low-volume products. Across all productions, RCP values exceeded the clinical release criterion of 95

Radiosynovectomy (RSV) relies on intra-articular administration of beta-emitting radiopharmaceuticals, where sufficient joint retention and minimal extra-articular leakage are critical determinants of therapeutic safety and efficacy. While 90Y-based agents are commonly used for large joints, alternative radionuclides with more favorable radiobiological characteristics may offer potential advantages. This preclinical study aimed to comparatively evaluate the intra-articular retention and leakage characteristics of in-house labeled lutetium-177-labeled macroaggregated albumin ([177Lu]Lu-MAA) and 90Y-resin following injection into a rat knee model. Ten female Wistar rats were divided into three groups. After radiolabeling and quality control of [177Lu]Lu-MAA (radiochemical purity >95%), intra-articular injections were performed. Serial SPECT/CT (and PET/CT for 90Y) imaging was conducted up to 144 h post-injection. Leakage percentages were calculated using VOI-based activity measurements adjusted for physical decay and compared using the Mann-Whitney U test. Both radiopharmaceuticals demonstrated high intra-articular retention at one week, with limited extra-articular leakage. Mean leakage percentages were 8.4% ± 2.7% for [177Lu]Lu-MAA and 6.0% ± 2.2% for 90Y-resin, with no statistically significant difference between groups (p = 0.22). Distinct biodistribution patterns were observed in leaked activity, with predominant colonic uptake in the 90Y group, whereas 177Lu leakage showed a distribution pattern consistent with free lutetium behavior. To our knowledge, this is the first preclinical study directly comparing intra-articular retention of [177Lu]Lu-MAA and 90Y-resin in a controlled rat knee model. The observed retention characteristics and leakage patterns support further investigation of [177Lu]Lu-MAA as a potential radiosynovectomy candidate in future translational studies.

OBJECTIVE:To assess the false positive gallium-68-labeled urea-based prostate-specific membrane antigen ( 68 Ga-PSMA) uptake rate in the prostate gland in patients with primary prostate cancer (PCa), and determine whether multiparametric prostate MRI (mpMRI) within hybrid PET/MRI can reduce false positives. METHODS:Fifty-one treatment-naive patients with PCa undergoing radical prostatectomy were prospectively recruited. All underwent 68 Ga-PSMA-11 PET/MRI with mpMRI. Images were assessed independently by the nuclear medicine physicians and radiologist using PRIMARY score and PIRADS v2.1, then jointly as fused PET/MRI. Radical prostatectomy followed imaging after a mean interval of 46 ± 32 days. Imaging findings were compared with postoperative histological mapping. Prostate was divided into sextants for lesion localization, and false positive uptake was recorded. Diagnostic performance metrics were calculated. RESULTS:Seven of 51 patients (13.7%) exhibited false positive PSMA uptake because of benign findings - asymmetrical central zone thickening, benign prostatic hyperplasia, or prostatitis. mpMRI was true negative in all. PET/MRI showed higher sensitivity and accuracy (74.9 and 83.0%) than PET (65.0 and 74.5%) and mpMRI (66.5 and 77.5%). For index lesion detection, PET/MRI had 92.2% sensitivity, outperforming PET (80.4%) and mpMRI (86.3%). PET/MRI was significantly more accurate than mpMRI ( P  < 0.001) and PET ( P  = 0.014), while PET and mpMRI were similar ( P  = 0.770). CONCLUSION:False positive 68 Ga-PSMA uptake is common and can affect clinical decisions, including focal therapy or recurrence assessment after radiotherapy. mpMRI helps clarify benign mimics, improving diagnostic accuracy. PET/MRI may offer more reliable assessment of PCa, potentially aiding focal therapy planning and posttreatment evaluation.

Purpose: The main purpose is to evaluate the safety, and efficacy of 177 Lutetium labeled macroaggregated albumin (LUTMA) ablation of thyroid nodules. Material and methods: Patients with confirmed benign nodules who were not candidate or did not accept surgery were enrolled. Under ultrasonography (USG) guidance, LUTMA which was produced in our department, was administered into the nodules. Nodule volumes were assessed via USG before the injection and at 1-week, 1-month, and 3-months post-treatment. We calculated the volume reduction rates (VRRs) for these intervals. To detect extranodular activity leakage, patients underwent SPECT/CT imaging at one hour, 24 hours, and one week post-injection. Results: Fifteen patients (male: 12, female: 3) with benign thyroid nodules were eligible to join this study. These nodules were categorized as cystic (n = 9), solid (n = 3), or mixed (n = 3). Median nodules volume was 6.59 ml (range: 0.56-55 ml). Predicted absorbed dosee to the nodules varied between 10 to 1036 Gy. The VRRs at 3. months was 85% for all nodule types with gradual increases over time: 0-92%, 20-97%, and 28-98% at 1. week, 1. month, and 3-months, respectively. The median VRR of cystic nodules was 89% (range: 81%-98%) at 3-months. It is significantly higher than solid ones (p = 0.009). None of the patients experienced adverse reactions or discomfort during the injection or follow-up. Conclusion: LUTMA treatment significantly reduces the volume of benign thyroid nodules, offering relief from disease-associated symptoms and cosmetic concerns. It emerges as a promising alternative to surgical and other local treatments for benign thyroid nodule ablation. Clinical signification: LUTMA is a novel theranostic radiopharmaceutical which is promising in local ablative treatment of benign thyroid nodules. (c) 2024 Sociedad Espanola ola de Medicina Nuclear e Imagen Molecular. Published by Elsevier Espana, a, S.L.U. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Objetivo El objetivo principal del estudio fue evaluar la seguridad y eficacia en la ablación de nódulos tiroideos mediante macroagregados de albúmina radiomarcada con 177Lutecio (LUTMA). Material y métodos Se incluyeron pacientes con nódulos benignos confirmados que no eran candidatos o no aceptaron la cirugía. Bajo control ecográfico, se inyectó el LUTMA producido en nuestro departamento. Se evaluó mediante ecografía el volumen de los nódulos antes de la inyección, así como a la semana y al mes y 3 meses después del tratamiento. Para estos tiempos se calculó la tasa de reducción de volumen (TRV). Para detectar una extravasación extranodular de la actividad, los pacientes fueron sometidos a un estudio SPECT/TC una hora, 24h y una semana después de la inyección. Resultados Quince pacientes (12 hombres; 3 mujeres) con nódulos tiroideos benignos fueron candidatos para participar en este estudio. Estos nódulos se clasificaron como quísticos (n=9), sólidos (n=3) o mixtos (n=3). La mediana del volumen de los nódulos fue de 6,59ml (rango: 0,56-55ml). La dosis absorbida esperada en los nódulos osciló entre los 10 y 1036Gy. La TRV a los 3 meses fue del 85% para todos los tipos de nódulo, con su aumento progresivo a lo largo del tiempo: 0-92%, 20-97% y 28-98% a la semana, al mes y a los 3 meses, respectivamente. La mediana de la TRV de los nódulos quísticos fue del 89% (rango: 81-98%) a los 3 meses, siendo significativamente superior a la de los nódulos sólidos (p=0,009). Ninguno de los pacientes presentó reacciones adversas o molestias durante la inyección ni durante el seguimiento. Conclusión El tratamiento con LUTMA redujo significativamente el volumen de los nódulos tiroideos benignos, ofreciendo una mejoría de los síntomas asociados a la enfermedad y a la cuestión estética. Este tratamiento se perfila como una alternativa prometedora frente al tratamiento quirúrgico o frente a otros tratamientos locales para la ablación de los nódulos tiroideos benignos. Importancia clínica LUTMA es un nuevo radiofármaco teragnóstico prometedor para el tratamiento ablativo local de los nódulos tiroideos benignos.

Objectives: The aim of this study is to evaluation of Tc-99m-hexamethylpropyleneamineoxime (HMPAO)-labeled leukocytes in terms of radiochemical, biochemical, and microbiological quality controls and to examine the effect of leukocyte numbers of the blood obtained from patients and the medications currently used by the patients on the radiochemical yields of Tc-99m-HMPAO-labeled leukocytes, and imaging quality was evaluated. Methods: Thirty paients were included in our study who applied to Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Department of Nuclear Medicine for Tc-99m-HMPAO-labeled leukocyte scintigraphy. Devices and chemicals used in the preparation of Tc-99m-HMPAO-labeled laukocytes were compared with other nuclear medicine clinics. Tc-99m-HMPAO-labeled leukocytes were evaluated in terms of radiochemical, biochemical, and microbiological quality controls. The effect of leukocyte numbers of the blood obtained from patients and the medications currently used by the patients on the radiochemical yields of Tc-99m-HMPAO-labeled leukocytes and imaging quality was evaluated. Results: The pH range of Tc-99m-HMPAO was 6-8 and the radiochemical purity was 90±2.04% (n=30), the radiochemical yield of Tc-99m-HMPAO-labeled leukocytes was 51±2.18% (n=30), the radiolabeling yield of Tc-99m-HMPAO-labeled leukocyte increased as the amount of white blood cell in the blood increased and whether the patients used any antibiotic, blood thinners, insulin and blood pressure medications did not affect the radiolabeling yield of Tc-99m-HMPAO-labeled leukocytes. The number of erythrocytes were removed at a rate of >99% in LPR by starch solution (6% HES; in the hemocytometric examination of Tc-99m-HMPAO-labeled leukocytes performed zeroth and 4th h, living/dead cell ratio was found 97.5% and the product was sterile. Conclusion: Tc-99m-HMPAO was labeled with leukocytes successfully, and Tc-99m-HMPAO-labeled leukocytes was safely injected to the patients as sterile without loss of vitality and aggregation.

Objective PET imaging with F-18 DOPA (FDOPA) and Ga-68 DOTATATE (TATE) shows the most promising results to detect medullary thyroid cancer (MTC) recurrence. We performed this comparative study to detect the site of recurrent or metastatic disease in MTC patients with elevated serum calcitonin (Ctn) and/or carcinoembryonic antigen (CEA) levels. Methods We studied 46 MTC patients (25 women, 21 men) with elevated Ctn and/or CEA levels during follow-up who had both FDOPA and TATE PET/CT scans for re-staging purposes. Results FDOPA PET imaging yielded an overall sensitivity of 86.8%, specificity of 100%, PPV of 100%, NPV of 61.5%, and accuracy of 89.1%, while TATE PET scan had the same values as 84.2%, 87.5%, 96.9%, 53.8%, and 84.6%, respectively, and there was no statistically significant difference between the two modalities with the exception of the specificity value that was higher for FDOPA imaging. In a subgroup of patients with overt Ctn or CEA elevation, sensitivity of FDOPA increased significantly, whereas TATE sensitivity did not change. FDOPA PET imaging was significantly superior in detecting liver and regional lymph node (LN) metastases, while TATE PET scan was significantly better in the skeletal metastases. Early FDOPA demonstrated 11 invisible lesions on late FDOPA. Conclusion Both FDOPA and TATE PET/CT imaging are useful to localize recurrences in MTC patients. While TATE imaging is superior to reveal skeletal disease, FDOPA seems better in liver and regional LN metastases; therefore, the two modalities appear complementary in monitoring MTC patients with elevated serum Ctn and/or CEA levels.

A number of radioactive tracers are currently being actively examined to image prostate-specific membrane antigen positive (PSMA+) tumors, especially in primary and recurrent prostate cancer. We report a first-in-human study of [18F]-BF3-Cy3-ACUPA by determining its safety, biodistribution, radiation dosimetry, and feasibility of tumor detection by preoperative positron emission tomography, as well as intraoperative fluorescence imaging, in patients with PSMA+ tumors. Background: A first-in-human study of [F-18]-BF3-Cy3-ACUPA, a small-molecule imaging agent that can be unimolecularly both positron emitting and fluorescent, is conducted to determine its safety, biodistribution, radiation dosimetry, feasibility in tumor detection by preoperative positron emission tomography (PET), as well as its intraoperative fluorescence imaging utility in patients with prostate-specific membrane antigen positive (PSMA(+)) tumors. Methods: Ten patients aged 66 +/- 7 years received a 6.5 +/- 3.2 mCi intravenous injection of [F-18]-BF3-Cy3-ACUPA and underwent PET/computed tomography (CT) imaging. Radiation dosimetry of [F-18]-BF3-Cy3-ACUPA, normal organ biodistribution, and tumor uptakes were examined. Two patients were prescheduled for radical prostatectomy (RP) with extended pelvic lymphadenectomy approximately 24 hours following [F-18]-BF3-Cy3-ACUPA injection and imaging. Without reinjection, intraoperative fluorescence imaging was performed on freshly excised tissue during RP. Frozen sections of excised tissue during RP were submitted for confirmatory histopathology and multiphoton fluorescence and brightfield microscopy. Results: Absorbed doses by organs including the kidneys and salivary glands were similar to 68Ga-PSMA-11 imaging. [F-18]-BF3-Cy3-ACUPA physiologic radiotracer accumulation and urinary/biliary excretion closely resembled the distribution of other published PSMA tracers including [F-18]-JK-PSMA-7, [F-18]-PSMA-1007, [F-18]-DCFPyL, and [F-18]-DCFBC. F-19-BF3-Cy3-ACUPA was retained in PSMA(+) cancer tissues in patients for at least 24 hours, allowing for intraoperative fluorescence assessment of the prostate and of the embedded prostate cancer without contrast reinjection. After 24 hours, the imaging agent mostly decayed or cleared from the blood pool. Preoperative PET and fluorescence imaging findings were confirmed with final histopathology and multiphoton microscopy. Conclusion: Our first-in-human results demonstrate that [F-18]-BF3-Cy3-ACUPA is safe and feasible in humans. Larger trials with this PET tracer are expected to further define its capabilities and its clinical role in the management of PSMA(+) tumors, especially in prostate cancer. (C) 2021 Elsevier Inc. All rights reserved.

OBJECTIVE:Our aim was to assess the diagnostic performance of F-18 fluorocholine (FCH) positron emission tomography/computed tomography (PET/CT) in detecting hyperfunctioning parathyroid tissue (HPT) in patients with elevated parathyroid hormone levels with negative or inconclusive conventional imaging results and to compare the findings with those obtained using technetium-99m sestamibi (MIBI) scintigraphy and neck ultrasonography (US).MATERIALS AND METHODS:Images of 105 patients with hyperparathyroidism who underwent FCH PET/CT, dual-phase MIBI parathyroid scintigraphy (median interval: 42 days), and neck US were retrospectively analyzed. The gold standard was histopathological findings for 81 patients who underwent parathyroidectomy and clinical follow-up findings in the remaining 24 patients. Sensitivities, positive predictive values (PPVs), and accuracies were calculated for all imaging modalities.RESULTS:Among the 81 patients who underwent parathyroidectomy, either parathyroid adenoma (n = 64), hyperplasia (n = 9), neoplasia (n = 4), or both parathyroid adenoma and hyperplasia (n = 1) were detected, except 3 patients who did not show HPT. Of the 24 (23%) patients who were followed-up without operation, 22 (92%) showed persistent hyperparathyroidism. FCH PET/CT showed significantly higher sensitivity than MIBI scintigraphy and US in detection of HPT (p < 0.01). Sensitivity, PPV, and accuracy of FCH PET/CT were 94.1% (95/101), 97.9% (95/97), and 92.4% (97/105), respectively. The corresponding values for MIBI scintigraphy and US were 45.1% (46/102), 97.9% (46/47), and 45.7% (48/105) and 44.1% (45/102), 93.8% (45/48), and 42.9% (45/105), respectively. Among the 35 patients showing negative MIBI scintigraphy and neck US findings, 30 (86%) showed positive results on FCH PET/CT. FCH PET/CT could demonstrate ectopic locations of HPT in 11 patients whereas MIBI and US showed positive findings in only 6 and 3 patients, respectively.CONCLUSION:FCH PET/CT is an effective imaging modality for detection of HPT with the highest sensitivity among the available imaging techniques. Therefore, FCH PET/CT can be recommended especially for patients who show negative or inconclusive results on conventional imaging.

Objectives: Gallium-68 (Ga-68) prostate specific membrane antigen (PSMA) positron emission tomography (PET) has been shown to be more accurate than multiparametric prostate magnetic resonance imaging (MRI) in detection of primary prostate lesions. Using hybrid PET/MRI we aim to detect the correlation between SUVmax and apparent diffusion coefficient (ADC) in primary prostate lesions and to assess their prognostic value in detection of lymph node (LN) metastasis. Methods: Twenty-six patients, who were diagnosed as having prostate cancer with biopsy and underwent Ga-68 PSMA PET/MRI together with biparametric prostate MRI (bpMRI) were included. SUVmax, SUVmean and ADC were recorded for index lesions drawing a region of interest (ROI) of 1 cm2 around the pixel with the highest SUVmax (ROI-1) and another ROI following borders of prostate tumor detected by bpMRI (ROI-2). Presence of LN metastasis was recorded according to PSMA PET/MRI. Results: SUVmax was inversely correlated with ADC (ROI-1: p=0.010; ROI-2: p=0.017 for b=800). SUVmax and SUVmeans were both higher in patients with LN metastasis and ADC was lower in patients with LN metastasis for ROI-1. SUVmax cut-off value of 19.8 for ROI-1 and 20.9 for ROI-2 had sensitivity and specificity of 77.8% and 76.5%, respectively for detection of LN metastasis, whereas ADC (b=800) cut-off value of 0.92x10-3 mm2/s had sensitivity and specificity of 87.5% and 76.5%, respectively. SUVmax/ADC (b=800) ratio increased the sensitivity and specificity to 100% and 82.4%, respectively. Conclusion: SUV and ADC values are inversely correlated in primary prostate lesions and the combined use of both values increases the diagnostic accuracy of hybrid PET/MRI in the detection of primary prostate lesions.

Background/aim The aim of our study was to compare Tc-99m MDP bone scan and Ga-68 PSMA PET/CT in terms of detection of bone metastasis in prostate cancer patients. Materials and methods A total of 28 prostate cancer patients with bone scan and PSMA PET/CT performed within 90 days were retrospectively included in our analysis. All bone lesions were scored as negative (score-0), positive (score-1), or suspicious (score-2) for metastasis by two experienced nuclear medicine physicians. Both patient-based and region-based analyses were made for all osseous lesions. Results On per-patient analysis; sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were 72.7%, 52.9%, 50%, 75%, and 60.7%, respectively, for bone scan and 90.9%, 100%, 100%, 94.4%, and 96.4%, respectively, for PSMA PET/CT. On per-region analysis; sensitivity, specificity, PPV, NPV, and accuracy were 76.2%, 80.9%, 57.1%, 91.1%, and 79.8%, respectively, for bone scan and 85.7%, 100%, 100%, 95.5%, and 95.4%, respectively, for PSMA PET/CT. Conclusion Ga-68 PSMA PET/CT has higher sensitivity, specificity, and accuracy compared to bone scan in terms of bone metastasis detection in prostate cancer patients. Therefore, it might be the modality of choice for patients with suspicion for metastatic disease, despite negative bone scan and conventional imaging results.

A number of different peptides or antibodies have been labeled with 177Lu and used for clinical imaging and treatment. To our knowledge, 177Lu had never before been used to label macroaggregated albumin, and our radiopharmacy laboratory at Istanbul University-Cerrahpaşa made a special effort to do so. We present the case of a 43-y-old man whose cystic thyroid nodule was treated with an intranodular injection of 177Lu-macroaggregated albumin and imaged with SPECT/CT.