Nuclear Medicine Communications最新文献

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.

Aim: Radiomics is an emerging field in medical imaging that leverages advanced computational algorithms to extract textural characteristics from medical images. It promises to transform breast cancer management by providing more accurate, reproducible, and noninvasive tools for clinicians, ultimately improving patient outcomes. We assessed the correlation of immunohistochemistry markers with textural characteristics derived from dual point F-18 fluorodeoxyglucose (FDG) positron emission tomography-computed tomograhy (PET-CT) in treatment naive locally advanced breast cancer patients.

Materials and methods: A total of 83 histopathologically proven, locally advanced breast cancer patients underwent baseline FDG PET-CT, 1-h postinjection. A total of 58 of 83 patients underwent PET-CT scan at 2-h postinjection. The primary lesion was segmented semiautomatically with 40% maximum standard uptake value (SUV max ) threshold, and textural characteristics were extracted using LIFEx software. Pearson correlation test was used to analyse relationships between textural metrics and immunohistochemistry markers (estrogen receptor, progesterone receptor, Her2neu, and Mib-1 index) of breast cancer.

Results: In 1-h FDG-PET, we observed no significant correlation between immunohistochemistry markers and textural parameters; however, in 2-h FDG-PET, there was moderate positive correlation of estrogen receptors with variance, moderate negative correlation with small-zone emphasis, zone-size nonuniformity, and grey-level variance (GLV). A moderate negative correlation of progesterone receptor with GLV and SUV max , a moderate positive correlation of Mib-1 index with volume, voxel counting, kurtosis, large zone emphasis, and a moderate negative correlation with skewness was observed. None of the parameters showed significant correlation with Her2neu.

Conclusion: This study indicates an association between textural parameters on delayed FDG PET-CT and immunohistochemistry markers. These textural parameters can be potentially useful in understanding tumor biology noninvasively.

Objective: Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) improve survival of EGFR-mutated lung adenocarcinoma (LUAD); however, outcomes vary with genetic subtypes and tumor heterogeneity in late-stage. We aimed to construct pretreatment 18 F-2-fluoro-2-deoxyglucose PET/computed tomography ( 18 F-FDG PET/CT) radiomics models for EGFR-subtype prediction and prognosis in first-line TKIs-treated patients.

Methods: We retrospectively analyzed 131 EGFR-mutated advanced LUAD patients from 2017 to 2024: 72 exon 19 deletion (19Del) and 59 exon 21 L858R (21L858R) mutations. After feature selection, support vector machine models: PET, CT, PET-CT, and clinical PET-CT combined models were built. Performance was evaluated by areas under the receiver operating characteristic curve (AUC), calibration curves, and decision curve analysis (DCA). Model-derived radscore was used to explore progression-free survival (PFS) in first-line EGFR-TKIs-treated patients. Multivariate Cox regression was conducted to identify independent factors.

Results: The clinical PET/CT combined model achieved AUCs of 0.854 [95% confidence interval (CI): 0.776-0.932] and 0.785 (95% CI: 0.639-0.932) in training and test sets. The calibration curves showed good agreement, and the DCA confirmed clinical utility. Among 125 successfully followed patients, 21L858R mutation patients showed poorer median PFS ( P  = 0.008) compared to 19Del mutation. High radscore [hazard ratio (HR): 0.57, 95% CI: 0.34-0.94, P  = 0.029], third-generation TKI therapy (HR: 0.45, 95% CI: 0.27-0.73, P  = 0.001), and high maximum standardized uptake value (HR: 1.67, 95% CI: 1.03-2.69, P  = 0.036) were independent factors of PFS.

Conclusion: Integrating 18 F-FDG PET/CT radiomics with clinical data precisely identifies EGFR mutation subtypes and guides initial TKI monotherapy in advanced LUAD.

Salivary gland scintigraphy (SGS) is a valuable imaging modality for assessing major salivary gland function, particularly in patients with Sjögren syndrome, and postradiotherapy conditions. Despite the existence of multiple quantitative analysis methods, clinical practice remains dominated by qualitative interpretation due to the lack of standardization, time-consuming procedures, and absence of user-friendly tools. In this study, we present a fully automated method for quantitative SGS analysis based on kinetic modeling of time-activity curves, implemented without altering standard imaging protocols, using a software we developed in-house on a Xeleris (GE HealthCare) workstation. The curves were segmented into uptake, excretion, and postexcretion phases, each fitted to specific kinetic models. From the fitted parameters, we derived functional variables, including vascular flow, active uptake, uptake velocity, total accumulation, absolute excretion, excretion fraction, and excretion rate. This approach enables rapid and reproducible extraction of functional data, with processing time under 5 s per study. We demonstrate its clinical utility through two case studies, highlighting how kinetic parameters reflect salivary gland function and its longitudinal changes. Our method bridges the gap between complex quantitative analysis and practical clinical application, offering a robust tool for monitoring disease progression and treatment response, potentially improving diagnostic reliability and research scalability.

Objective: This study aimed to introduce a computed tomography (CT)-based tissue segmentation technique to quantify the volume and metabolic activity of the arm muscles using [ 18 F]-fluorodeoxyglucose ([ 18 F]FDG) PET/CT.

Methods: Eighty-seven subjects from the CAMONA study were included. A semiautomated three-dimensional segmentation algorithm was used to highlight the muscle. The [ 18 F]FDG uptake was measured as mean standardized uptake value (SUV) normalized to body weight (SUV BW ) and to lean body mass (SUV LBM ). To acquire normalized volume, arm muscle volume, humerus volume, and humerus length were used. The average SUV mean was calculated from independently measured volumes (cm 3 ) of the left and right muscle groups. The obtained SUV BW , SUV LBM , and normalized volume were used to compare the right and left arms.

Results: Between right and left arm muscles, there was significantly higher uptake of SUV BW and SUV LBM in the right arm compared with the left ( P < 0.001). Between males and females, there was a significantly higher SUV BW in the right arm for females ( P = 0.03) and significantly higher normalized volume on both right and left arms for males (right, P < 0.001; left, P < 0.001).

Conclusion: [ 18 F]FDG PET/CT using CT-based segmentation enables analysis of total arm muscle metabolic activity and volume. This methodology demonstrated significant differences in mean SUV BW and SUV LBM between the left and right arms, with consistently higher uptake in the right arm. In addition, females exhibited higher SUV BW than males. The techniques developed in this study may also be applied to further investigate the laterality and metabolism of other muscle groups.

Purpose: This study aimed to investigate the differential patterns of anterior abdominal wall (AAW) radiotracer accumulation using pretherapeutic technetium-99m macroaggregated albumin ( 99m Tc-MAA) single photon emission computed tomography/computed tomography (SPECT/CT) and posttherapeutic yttrium-90 ( 90 Y) positron emission tomography/CT (PET/CT) imaging in 90 Y resin microspheres selective internal radiation therapy (SIRT).

Materials and methods: A retrospective analysis was conducted on 204 patients with unresectable liver malignancies who underwent SIRT between August 2022 and November 2024. Pretherapeutic evaluation included diagnostic angiography and 99m Tc-MAA imaging. Posttherapeutic 90 Y-PET/CT was performed within 24 h of treatment to verify microspheres distribution. Patients with AAW accumulation on 99m Tc-MAA images or 90 Y-microspheres PET/CT images were analyzed, and follow-up results for at least 3 months served as reference standards.

Results: Among 204 patients, 21 (10.3%) showed AAW accumulation on 99m Tc-MAA images or 90 Y-microspheres PET/CT images. Concordant findings between 99m Tc-MAA images and 90 Y-PET/CT images were observed in 11(11/21, 52.4%) cases, while five cases (5/21, 23.8%) showed accumulation only on 90 Y-PET/CT images, and the other five cases (5/21, 23.8%) showed accumulation only on 99m Tc-MAA images. The hepatic falciform artery (HFA) was found in two patients. Mild abdominal pain was observed in four patients, and only one patient experienced abdominal dermatitis, which resolved spontaneously. The remaining patients did not experience any relevant side effects during the follow-up period.

Conclusion: AAW-related complications were infrequent and mild, suggesting that a patent HFA may not be considered a contraindication for SIRT; however, discordance between 99m Tc-MAA and 90 Y-PET/CT highlights the need for vigilant posttreatment monitoring, even in cases without pretherapeutic AAW accumulation.

Aim: This study aimed to evaluate the accuracy of the 6-month evaluation to accept treatment failure after a single dose of radioactive iodine (RAI) for Graves' disease and to decide whether to repeat the dose.

Methods: This study retrospectively analyzed 104 patients who received a single dose of RAI between 2003 and 2022, had regular follow-up for at least 2 years, and did not have extrathyroidal symptoms. The study group was divided into two groups: patients who developed hypothyroidism within the first 6 months and patients who developed hypothyroidism after 6 months, and statistically analyzed.

Results: The mean administered dose of RAI was 10.6 ± 4.4 mCi, and the average duration of hypothyroidism was 5.5 ± 5.4 months. In patients with late-onset hypothyroidism (>6 months), the 2-h iodine uptake values were significantly higher, and post-RAI thyroid-stimulating hormone levels were significantly lower. While 58.5% of patients with early-onset hypothyroidism (<6 months) required antithyroid drug (ATD) therapy after RAI, all patients who developed hypothyroidism after 6 months received supportive ATD treatment. The 24-h iodine uptake values were significantly higher in the hypothyroid group compared with the euthyroid group. During follow-up, 26.9% of patients were hypothyroid at 0-3 months, 62.5% at 3-6 months, and 77.9% at 12 months. While 20.2% of patients remained hyperthyroid at 6 months, this rate declined to 3.8% at 12 months.

Conclusion: This study suggests that the 6 th month following RAI treatment in patients with Graves' disease may not be sufficient to assess treatment response, as hypothyroidism tends to develop cumulatively over time. Iodine uptake values at 2 and 24 h may serve as useful indicators for predicting the development of early or late hypothyroidism, while also helping to guide the maintenance of a euthyroid state.

Adult-onset Still's disease (AOSD) is a rare systemic inflammatory disorder that frequently presents as fever of unknown origin (FUO), posing a diagnostic challenge. This study aimed to systematically review the diagnostic utility of 18 F-labeled fluorodeoxyglucose ( 18 F-FDG) PET/computed tomography (CT) in AOSD. A systematic review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and registered in PROSPERO (CRD42023443831). Databases searched included PubMed, EMBASE, and Ovid up to December 2022. We included case reports, case series, cross-sectional, case-control, cohort studies, and clinical trials reporting PET/CT findings in adult patients diagnosed with AOSD. Data extraction included demographics, PET/CT findings, tracers used, standardized uptake values (SUVs), and diagnostic criteria applied. Data were analyzed following the SWiM framework because of heterogeneity. From 155 records, 54 studies (545 patients) were included. The majority were case reports or series ( n  = 40), with 14 observational studies or trials. 18 F-FDG was used in 85% of cases, predominantly for diagnostic purposes (77.7%). The most commonly used diagnostic criteria were Yamaguchi (63%). The highest maximum SUV (SUV max ) values were observed in the bone marrow (4.0 ± 1.4), spleen (4.0 ± 1.9), and liver (4.2 ± 2.1). PET/CT findings frequently revealed diffuse hypermetabolism in these organs, aiding in distinguishing AOSD from infectious or malignant etiologies. 18 F-FDG PET/CT appears to be a useful adjunct in the diagnostic workup of AOSD, especially in cases presenting as FUO. Typical uptake patterns in bone marrow, spleen, liver, and lymph nodes may support the diagnosis, though biopsy remains essential to exclude neoplastic mimics.