Nuclear Medicine Communications最新文献

Objective: The aim of this study was to determine the rate of metastasis types in prostate cancer (PCa) patients with bone metastasis and to evaluate the relationship between volumetric parameters obtained from gallium-68 ( 68 Ga) prostate-specific membrane antigen (PSMA) PET/computed tomography (CT) and prostate-specific antigen (PSA) levels.

Materials and methods: We retrospectively reviewed the images of patients who underwent 68 Ga-PSMA PET/CT for restaging for recurrent PCa between 2014 and 2019. All detected bone lesions were manually grouped as 'osteoblastic (OB), osteolytic (OL), mixed (M), and radio-occult (RO) lesions' and the number and percentage were determined. Different volumetric values are obtained for each type of bone metastasis using the LIFEx v7.3.0 program. The relationship between PSA level and these volumetric values will be determined by the Spearman correlation test. The relationship between the International Society of Urological Pathology (ISUP) PCa grade group and volumetric values will be evaluated by the Kruskal-Wallis correlation test.

Results: Seventy-one patients had a total of 599 bone metastasis. Of these lesions, 268 were OB (44.7%), 39 were OL (6.5%), 72 were M (12.0%), and 220 were RO (36.7%). Total lesion volume (TLV) (P : 0.001), total lesion activity (TLA) (P : 0.001), and OB-TLA (P : 0.042) were significantly different between ISUP grades. In addition, the total number of lesions showed a statistically significant difference between ISUP grades (P : 0.019). PSA level correlated with RO lesion number ( r : 0.404, P : 0.016), RO-TLV ( r : 0.471, P : 0.004), and RO-TLA ( r : 0.528, P : 0.001).

Conclusion: 68 Ga-PSMA PET/CT can identify the source of biochemical recurrence by detecting RO lesions at early stages when bone mineral density is not affected.

Background: Lymphoma staging plays a pivotal role in treatment planning and prognosis. Yet, it still relies on manual interpretation of PET/computed tomography (CT) images, which is time-consuming, subjective, and prone to variability. This study introduces a novel radiomics-based machine learning model for automated lymphoma staging to improve diagnostic accuracy and streamline clinical workflow.

Methods: Imaging data from 241 patients with histologically confirmed lymphoma were retrospectively analyzed. Radiomics features were extracted from segmented lymph nodes and extranodal lesions using PET/CT. Three machine learning classifiers (Logistic Regression, Random Forest, and XGBoost) were trained to distinguish between early-stage (I-II) and advanced-stage (III-IV) lymphoma. Model performance was evaluated using area under the curve (AUC), sensitivity, specificity, and accuracy together with survival analysis.

Results: Among the three models evaluated, the logistic regression model incorporating both nodal and extranodal radiomic features performed the best, achieving an AUC of 0.87 and a sensitivity of 0.88 in the external validation cohort. Including extranodal features significantly improved classification accuracy compared to nodal-only models (AUC: 0.87 vs. 0.75). Survival analysis revealed advanced-stage patients had a fourfold higher mortality risk (hazard ratio: 0.22-0.26, P = 0.0036) and a median survival of 84 months. Key radiomic features, such as tumor shape irregularity and heterogeneity, were strongly associated with staging, aligning with Lugano criteria for extranodal spread.

Conclusion: This study demonstrated the potential of PET radiomics features for automated Lugano staging. Adding extranodal features significantly improved staging accuracy and informed treatment.

Purpose: Hibernating myocardium is a viable but dysfunctional myocardium state caused by chronic ischemia, with potential for recovery postrevascularization. This study evaluates the feasibility of transfer learning for predicting hibernating myocardium from rest myocardial perfusion images.

Methods: Patients who underwent myocardial viability assessment from January 2017 to September 2022 were split into training (70%) and validation (30%) sets, while those from October 2022 to January 2023 formed the testing set. Hibernating myocardium was defined as a mismatched perfusion-metabolism defect with impaired contractility. Rest myocardial perfusion polar maps were embedded using Google's InceptionV3, followed by data normalization and analysis of variance-based feature selection. Three gradient boosting algorithms were trained with stratified 10-fold cross-validation, validated, and tested. Performance was assessed using area under the curve (AUC), classification accuracy (CA), F1 score, specificity, and model interpretability via SHapley Additive exPlanations (SHAP) plots.

Results: The study included 239 patients (214 males, 25 females, mean age 56 ± 11 years); 123 (51.5%) had hibernating myocardium. All models achieved >0.700 in performance metrics across all datasets. Among them, extreme gradient boosting (xgboost) performed best on the test set (F1 score: 0.800, CA: 0.774, specificity: 0.909, AUC: 0.782). Beeswarm SHAP plots revealed a clear pattern of model interpretability for all models.

Conclusion: This study demonstrates the feasibility of transfer learning for predicting hibernating myocardium from rest myocardial perfusion images. The integration of deep convolutional neural networks with gradient boosting models highlights the potential of machine learning-based myocardial viability assessment, contributing valuable early evidence.

Objective: The efficacy of radioactive iodine-131 (RAI) therapy for Graves' disease (GD) depends on thyroid iodine uptake, which may be influenced by iodine status. This study investigated the relationship between urinary iodine concentration (UIC) and RAI uptake (RAIU) in newly diagnosed, drug-naive GD patients.

Methods: We retrospectively analyzed 248 patients with GD who underwent RAIU measurements at 2, 4, and 24 h after iodine-131 administration. UIC was measured using arsenic-cerium catalytic spectrophotometry. RAIU was calculated using standardized counts, and correlations with UIC were assessed via Pearson's correlation and linear regression. Group comparisons were performed with analysis of variance or Mann-Whitney U tests.

Results: The median UIC was 222.52 μg/L. Female patients had higher RAIU than males at all time points. RAIU declined with age ( P < 0.05). Elevated UIC showed significant inverse correlations with RAIU-2 h ( r = -0.15, P = 0.015), RAIU-4 h ( r = -0.21, P = 0.001), and RAIU-24 h ( r = -0.28, P < 0.001). Notably, patients with UIC > 300 μg/L demonstrated a 15-20% reduction in RAIU compared with those with normal UIC (100-300 μg/L). Gender, age, and some renal function indices showed no significant correlation with UIC.

Conclusion: This retrospective study adds some quantitative evidence on the relationship between UIC and RAIU in patients with newly diagnosed GD, further demonstrating that higher UIC values are associated with suppressed RAIU. These findings highlight the importance of pre-therapeutic UIC screening to optimize RAI dosing and planning, particularly in regions with variable dietary iodine intake.

This systematic review aimed to synthesize published data on the application of gallium-68 pentixafor PET/computed tomography ([68Ga]Ga-Pentixafor PET/CT) or PET/MRI (PET/MRI) in patients diagnosed with various lymphomas and solid malignancies. A comprehensive literature search was conducted across Cochrane, Ovid PubMed/MEDLINE, and Embase databases for articles indexed up to July 2023. Thirty-seven studies or subsets within studies met the inclusion criteria for analysis. Key findings indicate that lymphomas, including those with low [18F]FDG avidity such as lymphoplasmacytic lymphoma, chronic lymphocytic leukemia, marginal zone lymphoma (MZL), and central nervous system lymphoma, demonstrate [68Ga]Ga-Pentixafor avidity. Among lymphomas, mantle cell lymphoma and MZL showed particularly high uptake. [68Ga]Ga-Pentixafor PET/CT or PET/MRI demonstrated utility for staging and treatment response assessment in several solid tumors, including lung cancer [small-cell lung cancer, large cell neuroendocrine carcinoma of the lung (LCNEC), nonsmall cell lung cancer (adenocarcinoma (AC), squamous cell carcinoma (SCC))], glioblastoma multiform, vestibular schwannoma, desmoplastic small round cell tumor, esophageal cancer, and aldosterone-producing adenoma. The review suggests that [68Ga]Ga-Pentixafor PET holds promise for personalized diagnosis and therapy, potentially offering advantages over [18F]FDG PET in certain malignant conditions. Despite limitations such as study heterogeneity and varying patient numbers per tumor type, [68Ga]Ga-Pentixafor PET is a potentially valuable imaging modality for staging and response evaluation, particularly in nonsolid malignancies like lymphomas. Further research is needed to fully clarify its role in solid tumors.

Background: Lutetium-177 (Lu-177) prostate-specific membrane antigen (PSMA) therapy is an emerging treatment for metastatic castration-resistant prostate cancer (mCRPC), but there is limited evidence on whether imaging can predict treatment-related toxicity. This study investigated whether pretreatment PSMA PET imaging parameters could forecast toxicity and outcomes in Asian patients undergoing Lu-177 PSMA therapy.

Patients and methods: In this retrospective analysis, men with mCRPC treated with Lu-177 PSMA-617 at Koo Foundation Sun Yat-Sen Cancer Center, Taipei, were reviewed. Baseline Ga-68 PSMA-11 PET imaging metrics - including standardized uptake values (SUV), total lesion PSMA (TLP), and total tumor volume (TTV) - were assessed. Treatment response was measured by prostate-specific antigen (PSA) decline, and adverse effects and survival were evaluated from clinical records.

Results: Eighteen men (median age: 75, range: 55-91) received a median of 2 (range: 1-6) cycles of Lu-177 PSMA therapy, with a mean administered radioactivity of 7.0 GBq (range: 3.0-7.4 GBq) per cycle. Grade 3/4 hematologic toxicities occurred in six (33.3%) patients, with thrombocytopenia (27.8%) and anemia (22.2%) most common. Higher TLP and TTV were linked to increased toxicity and poorer survival, while higher SUVmean was associated with better PSA response.

Conclusion: Pretreatment PSMA PET imaging may help predict adverse effects in Asian mCRPC patients undergoing Lu-177 PSMA therapy. Larger, prospective studies are needed for confirmation.

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.