Nuclear Medicine Communications最新文献

Objective: To assess the diagnostic value of fluorine 18 ( 18 F)-labeled prostate-specific membrane antigen (PSMA)-1007 PET/MRI and compare with that of 18 F-PSMA-1007 PET/computed tomography (CT) for biochemical recurrence (BCR) of prostate cancer (PCa) after radical prostatectomy.

Materials and methods: We enrolled 40 patients who underwent 18 F-PSMA-1007 PET/CT and 18 F-PSMA-1007 PET/MRI for BCR after radical prostatectomy. Two readers independently assessed the images and determined their overall assessment of positive lesions on PET/MRI and PET/CT. The association between the patients' clinical characteristics and positive detection results on the PET/CT and PET/MRI was explored. The PET/CT and PET/MRI results were verified during a 24-month follow-up to calculate their diagnostic accuracy.

Results: The detection rate of positive patients on 18 F-PSMA-1007 PET/CT and PET/MRI were consistent, with a value of 77.50%. The positive detection results were moderately associated with the patients' prostate-specific antigen (PSA) levels at examination, and the detection rate increased significantly with values of 50.00%, 72.73%, 90.91%, and 100% for PSA levels <0.5, 0.5-<1.0, 1.0-<2.0, and ≥2.0 ng/ml, respectively. Conclusive follow-up for affirmation or refutation of PCa recurrence was available for 33 patients. Compared with the follow-up results, on the patient-based level, the diagnostic accuracies for PET/MRI and PET/CT were both 100%. On the lesion-based level, PET/MRI excluded a false positive of bone metastasis on PET/CT.

Conclusion: 18 F-PSMA-1007 PET/MRI and 18 F-PSMA-1007 PET/CT demonstrate almost equal diagnostic value in detecting BCR, but PET/MRI can provide more lesion information, facilitating diagnosis and treatment due to its superior soft tissue resolution.

Gastric emptying scintigraphy provides a physiologic, noninvasive, and quantitative measurement of gastric emptying. Consensus guidelines recommended a standardized meal that consisted of an egg substitute equal to two whole eggs labeled with sulphur colloid ([ 99m Tc]Tc-SC), two slices of bread, jam, and 120 mL of water. Previous studies reported the use of commercial liquid nutrient meal (LNM) as a suitable meal for patients with egg allergy. Our work proposes an alternative recipe based on cooking commercial LNM as a pancake, and evaluates the stability of binding of several radiopharmaceuticals in simulated gastric medium, concluding that [ 99m Tc]Tc-MAA binds to LNM pancakes in percentages ≥90%, similar to scrambled eggs standardized meal, so that [ 99m Tc]Tc-MAA-LNM in pancakes could be a good alternative for patients who have allergies to eggs, intolerance to LNM or difficulties for finishing the entire standard meal, as for instance pediatric patients for whom pancakes should be an attractive recipe.

Background: Thyroid incidentalomas (TIs) are incidental thyroid lesions detected on fluorodeoxy- d -glucose ( 18 F-FDG) PET/computed tomography (PET/CT) scans. This study aims to investigate the role of noninvasive PET/CT-derived radiomic features in characterizing 18 F-FDG PET/CT TIs and distinguishing benign from malignant thyroid lesions in oncological patients.

Materials and methods: We included 46 patients with PET/CT TIs who underwent thyroid ultrasound and thyroid surgery at our oncological referral hospital. Radiomic features extracted from regions of interest (ROI) in both PET and CT images and analyzed for their association with thyroid cancer and their predictive ability. The TIs were graded using the ultrasound TIRADS classification, and histopathological results served as the reference standard. Univariate and multivariate analyses were performed using features from each modality individually and combined. The performance of radiomic features was compared to the TIRADS classification.

Results: Among the 46 included patients, 36 patients (78%) had malignant thyroid lesions, while 10 patients (22%) had benign lesions. The combined run length nonuniformity radiomic feature from PET and CT cubical ROIs demonstrated the highest area under the curve (AUC) of 0.88 ( P < 0.05), with a negative correlation with malignancy. This performance was comparable to the TIRADS classification (AUC: 0.84, P < 0.05), which showed a positive correlation with thyroid cancer. Multivariate analysis showed higher predictive performance using CT-derived radiomics (AUC: 0.86 ± 0.13) compared to TIRADS (AUC: 0.80 ± 0.08).

Conclusion: This study highlights the potential of 18 F-FDG PET/CT-derived radiomics to distinguish benign from malignant thyroid lesions. Further studies with larger cohorts and deep learning-based methods could obtain more robust results.

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.