In this study, we aimed to evaluate the association between liver clearance values obtained from pre-treatment [⁹⁹ᵐTc]mebrofenin hepatobiliary scintigraphy and conventional liver function scores and biochemical parameters, and to perform an exploratory prognostic assessment of whether baseline clearance is associated with post-treatment outcomes, including overall survival, prior to ⁹⁰Y radioembolization. We also compared the functional assessment of the treatment region (based on mebrofenin uptake) with its anatomical CT volume (derived from [⁹⁹ᵐTc]macroaggregated albumin SPECT/CT) to determine the concordance between functional and volumetric data. Pre-treatment [⁹⁹ᵐTc]mebrofenin and [⁹⁹ᵐTc]MAA scintigraphies were performed in 19 patients scheduled to receive Yttrium-90 (90Y) microsphere therapy. Mebrofenin clearance was calculated, and its association with biochemical parameters and overall survival was examined. The functional definition of the planned treatment territory was estimated based on mebrofenin uptake, and this was compared with the anatomical volume of the same region on MAA SPECT/CT. Mebrofenin liver clearance showed significant (p < 0.05) negative correlations with pre- and post-treatment total and direct bilirubin levels and a positive correlation with post-treatment albumin. Clearance also demonstrated a strong inverse correlation with ALBI score (p < 0.05). Among biochemical changes, only the post-treatment change in direct bilirubin was significantly associated with clearance (p < 0.05). Functional and volumetric definitions of the treatment area showed strong correlation (ρ = 0.837, p < 0.001). In five patients with target ratio greater than 50

A 56-year-old male patient underwent total thyroidectomy, and pathology revealed multicentric papillary thyroid cancer. His post-operative stimulated thyroglobulin value was >500 ng/mL. 18F-fluorodeoxyglucose positron emission tomography (PET) computed tomography revealed hypermetabolic metastatic pulmonary nodules, cervical, and mediastinal lymph nodes. There was also a hypermetabolic lesion in the left gluteal muscle. Due to the patient's history of a pilonidal cyst in the same region, the possibility of an abscess was also considered, and due to the absence of radioactive iodine (RAI) uptake in the lesion, follow-up was deemed appropriate. During follow-up, as the patient progressed to RAI-refractory state, 68Ga-DOTATATE PET/magnetic resonance imaging, which was done for radionuclide therapy planning, revealed heterogeneously increased uptake in the gluteal lesion. A subsequent biopsy confirmed the diagnosis of PTC metastasis.

This study evaluates the impact of prior PRRT with Lu-177 DOTATATE on the response to TARE in NET patients with liver metastases. Twenty-one patients who underwent TARE after PRRT between 2015 and 2022 were retrospectively analyzed. Tumor-specific cumulative Lu-177 DOTATATE counts were calculated from SPECT/CT images. Treatment planning was conducted with a standard target dose of 150 Gy to the tumoral tissue. Treatment response was assessed using changes in SUVmax, SUVmean, and somatostatin receptor-expressing tumor volume (SRE-TV) values derived from Ga-68 DOTATATE PET/CT before and 2–4 months after TARE. Lesion size was evaluated using RECIST v1.1 criteria. Dosimetry calculations were performed on Tc-99 m MAA SPECT/CT and Y-90 microsphere PET/MRI using Simplicit90Y™. Statistical analyses included Spearman correlation and Kruskal–Wallis tests. The median age of patients was 56 years (range 36–78 years). PRRT involved a mean cumulative Lu-177 DOTATATE dose of 43.5 ± 13.4 GBq (1175 ± 362 mCi). Post-TARE reductions in SUVmax (38.49 ± 20.46 to 19.94 ± 10.43 g/mL), SUVmean (9.51 ± 5.60 to 5.39 ± 3.64 g/mL), and SRE-TV (217.43 ± 155.87 to 175.62 ± 147.77 cm3) were observed. No significant correlation was found between cumulative Lu-177 DOTATATE counts and changes in SUV parameters, SRE-TV values, or lesion size after TARE. Similarly, no correlation was detected between tumor-to-normal liver activity ratios, calculated using either the partition model or voxel-based dosimetry and cumulative Lu-177 DOTATATE counts. Prior PRRT does not significantly affect TARE response in NET patients with liver metastases. Radioembolization planning should prioritize factors like tumor, target, or healthy liver doses over previous PRRT.

We describe a case of a 57-year-old woman with isolated immunoglobulin G4-related disorder affecting her lacrimal glands. Pre-treatment 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (18F-FDG PET/CT) showed diffuse enlargement and increased FDG uptake in both lacrimal glands. After immunosuppressive treatment, 18F-FDG PET/CT showed no significant FDG uptake, and the sizes of both glands returned to normal.

OBJECTIVES:Radioactive iodine-refractory differentiated thyroid cancer (RAIR-DTC) is associated with challenges in both imaging and treatment due to resistance to I-131. The aim of this study is to compare the lesion detection rates of [ 18 F] fluorodeoxyglucose (FDG) PET/computed tomography [CT] and [ 68 Ga]Ga-prostate specific membrane antigen (PSMA)-11 PET/CT, and to investigate the theranostic potential of PSMA in RAIR-DTC. METHODS:Thirty-eight RAIR-DTC patients followed between 2022 and 2024 underwent [ 18 F]FDG PET/CT and [ 68 Ga]Ga-PSMA-11 PET/CT. Lesions with uptake exceeding background activity were considered positive, while physiological uptake areas and benign-appearing foci were excluded. Lesion maximum standardized uptake value (SUVmax), tumor-to-background ratio (TBR), and detection rates were calculated and compared. RESULTS:[ 18 F]FDG PET/CT detected more lesions overall than [ 68 Ga]Ga-PSMA-11 PET/CT (96.8 vs. 60.1%), particularly in the thyroid bed, lymph nodes, and lungs. However, both modalities identified the same number of bone lesions. While [ 18 F]FDG PET/CT was superior in most patients, [ 68 Ga]Ga-PSMA-11 PET/CT detected more lesions in a subset of patients and performed better in the pure classic papillary thyroid carcinoma subtype compared to other subtypes (71.7 vs. 50.3%). SUVmax and TBR values were higher on [ 18 F]FDG PET/CT, yet in 14 patients (36.8%), [ 68 Ga]Ga-PSMA-11 PET/CT identified lesions with SUVmax exceeding liver SUVmax, indicating potential eligibility for PSMA-based radionuclide therapy. CONCLUSION:Although [ 18 F]FDG PET/CT demonstrated superior overall lesion detection, [ 68 Ga]Ga-PSMA-11 PET/CT identified more lesions in a subset of patients. [ 68 Ga]Ga-PSMA-11 PET/CT appears to be more beneficial in the pure classic subtype compared to other histological variants. Notably, [ 68 Ga]Ga-PSMA-11 PET/CT demonstrated high uptake in a considerable number of patients and may provide theranostic value in RAIR-DTC patients with limited treatment options.

Objective: Our aim is to assess if there is a relationship between maximum standardized uptake (SUVmax) and apparent diffusion coefficient (ADC) values of reactive and metastatic lymph nodes, also to compare ADC values of reactive and metastatic lymph nodes in prostate cancer patients. Materials and Methods:We have retrospectively investigated 20 patients diagnosed with prostate cancer who underwent Ga-68 PSMA PET/MR imaging.Three metastatic and three reactive lymph nodes classified according to PSMA Ga-68 uptake in PET/MR were chosen for each patient.SUVmax and ADCmean values were calculated for each lymph node separately.SPSS version 22 was used for statistical analysis.Results: A total of 120 lymph nodes in 20 prostate cancer patients were assessed.There was a weak negative correlation between SUVmax values and ADCmean values of metastatic lymph nodes (p=0.009,r=-0.333).However, there was no significant correlation between SUVmax values and ADCmean values of reactive lymph nodes (p=0,271, r=-0,144).ADCmean values of metastatic lymph nodes were significantly lower than those of reactive lymph nodes (p=0.0001).Conclusion: PET/MR, which combines both advantages of PET and MRI, is an important tool for the diagnosis and management of prostate cancer.We have found that SUVmax values of metastatic lymph nodes were inversely correlated with ADCmean values and combination of both parameters may increase the diagnostic accuracy of Ga-68 PSMA PET/MR in the detection of lymph node metastasis.