Nuclear Medicine Communications最新文献

Background: This study evaluates the diagnostic value of PET/computed tomography imaging features using dual tracers, 18 F-fluorodeoxyglucose ( 18 F-FDG) and 18 F-fluorothymidine ( 18 F-FLT), combined with metabolic parameters and clinical characteristics, to differentiate benign and malignant pulmonary occupying lesions (POLs).

Methods: This retrospective study included 81 patients with pathologically confirmed POLs (median age = 59, interquartile range 49-69), with tissue obtained by bronchoscopic biopsy, percutaneous transthoracic needle biopsy, or surgical resection. We analyzed 18 F-FDG and 18 F-FLT PET imaging features (geometry, intensity, and texture) alongside clinical data and metabolic parameters to construct a combined prediction model.

Results: The predictive model integrating dual-tracer ( 18 F-FDG and 18 F-FLT) PET radiomics, metabolic parameters, and clinical characteristics demonstrated strong diagnostic performance. Malignant lesions were associated with significantly higher age, 18 F-FLT maximum standardized uptake value (SUVmax), and FLT/FDG SUVmax ratio compared to benign cases (all P  < 0.05). In the test cohort (25 cases: 13 benign, 12 malignant), the radiomics model outperformed the metabolic-clinical model, with area under the receiver operating characteristic curve (AUC) values of 0.962 [95% confidence interval (CI): 0.883-1.000] vs. 0.718 (95% CI: 0.496-0.940). The nomogram combining multimodal features achieved optimal performance (AUC: 0.981; 95% CI: 0.942-1.000), though the upper CI limit (1.000) may reflect high predictive accuracy tempered by small-sample variability. Decision curve analysis confirmed the nomogram's superior clinical net benefit over radiologists' judgment and single-modality models. Calibration curves showed excellent agreement between predicted probabilities and observed outcomes.

Conclusion: The dual-tracer radiomics model significantly enhances the differential diagnosis of benign and malignant pulmonary lesions, with the nomogram offering high clinical application potential.

Objective: Radioembolization-induced liver disease (REILD) is a potentially life-threatening complication that can develop after yttrium-90 (Y-90) radioembolization. Our study determined to find associations between liver toxicity and Y-90 dosimetry.

Methods: We analyzed cases of REILD and isolated hyperbilirubinemia that developed after Y-90 resin microsphere radioembolization for hepatocellular carcinoma with a focus on dosimetric parameters.

Results: Out of a cohort of 413 patients, 12 patients developed REILD, and 17 patients had grade 3 isolated hyperbilirubinemia. All patients in the REILD group were Barcelona-Clinic Liver Cancer (BCLC) stage C, with portal vein thrombosis (PVT) on baseline imaging, and albumin-bilirubin (ALBI) score of 2. More cases of REILD had bilobar radioembolization compared with unilobar treatment. The median absorbed dose to nontumorous liver was 33.0 and 31.8 Gy for REILD and isolated hyperbilirubinemia, respectively. The median overall survival (mOS) for the REILD group was 5.1 months [interquartile range (IQR): 3.4-8.6 months], while mOS for the isolated hyperbilirubinemia group was 4.3 months (IQR: 2.9-5.3 months). Comparing patients with BCLC stage C in the larger database, those who developed REILD had poorer overall survival outcomes.

Conclusion: Our study observed severe liver toxicity at absorbed doses below the recommended dose thresholds to nontumorous liver. ALBI scores greater than or equal to 2 predicted for postprocedural liver toxicities. Further prospective research is suggested to ascertain a safe absorbed dose threshold, incorporating ALBI, PVT status, and bilobar involvement. Caution is warranted when performing bilobar Y-90 radioembolization in ALBI greater than or equal to 2 patients, even at standard doses.

Background: Accurate lesion volume estimation is essential for reliable voxel-based dosimetry in Lu-177 radionuclide therapy. Conventional fixed-threshold segmentation-particularly the commonly used 40% threshold-can markedly underestimate small lesions due to partial volume effects, leading to substantial errors in quantitative SPECT-based dosimetry.

Purpose: This study systematically evaluated the relationship between lesion size and optimal threshold values in Lu-177 SPECT/CT imaging, quantified deviations introduced by the fixed 40% threshold, and established size-specific adaptive thresholds to improve segmentation and activity recovery accuracy.

Methods: A NEMA IEC body phantom with six spherical inserts (0.52-26.5 cm³) was filled with 20 mCi (740 MBq) Lu-177 at an 8 : 1 lesion-to-background ratio. SPECT/CT data were acquired using 60-90 projections with 10-20 s per frame. Images were reconstructed under 180 parameter combinations varying iterations, subsets, and filters. For each sphere, segmentation was performed using the fixed 40% threshold (40%ThS) and an adaptive, volume-matched threshold (AV%ThS) that reproduced the true physical volume.

Results: Optimal thresholds showed a strong inverse correlation with lesion size, decreasing from ~83% (1.15 cm³) to ~42% (26.5 cm³). The fixed 40% threshold substantially underestimated volumes less than 25 cm³, with quantitative deviations reaching 45% compared to AV%ThS. Best quantitative recovery was achieved with 90 projections × 20 s and OSEM 10 × 10 iterations/subsets with Butterworth filtering (0.45 cycles/cm, order 10).

Conclusion: A single fixed threshold is insufficient for accurate Lu-177 SPECT/CT dosimetry across diverse lesion sizes. Size-adaptive thresholding combined with optimized reconstruction parameters improves lesion delineation, enhances quantitative accuracy, and reduces dosimetric uncertainty in clinical practice.

Purpose: To evaluate the predictive value of 18F-fluorodeoxyglucose (18F-FDG) PET/computed tomography (CT) imaging features - including standardized uptake value (SUV), tumor-to-background ratio (TBR), metabolic tumor volume (MTV), and others - for overall survival (OS) in patients with glioma, and to clarify their clinical significance as independent prognostic factors.

Methods: This prospective cohort study enrolled 121 patients with pathologically confirmed glioma between January 2012 and December 2022. All patients underwent 18F-FDG PET/CT within 1 month before surgery. Metabolic parameters, including maximum/mean/minimum SUV (SUVmax, SUVmean, and SUVmin), TBRmax, MTV, and total lesion glycolysis (TLG), were extracted. Kaplan-Meier survival curves were generated, and differences in OS between parameter-stratified groups (high vs. low levels) were compared using log-rank tests. Univariate and multivariate Cox proportional hazards regression models were employed to identify independent prognostic factors for OS.

Results: Survival analysis revealed that high SUVmax, SUVmean, TBRmax, and TLG were significantly associated with reduced OS (log-rank P < 0.05). Multivariate Cox regression demonstrated that WHO grade III [adjusted hazard ratio = 8.99, 95% confidence interval (CI): 3.80-21.06], WHO grade IV (adjusted hazard ratio = 12.97, 95% CI: 5.81-42.00), isocitrate dehydrogenase (IDH) wild-type status (adjusted hazard ratio = 2.03, 95% CI: 1.18-3.51, P = 0.011), high SUVmax (adjusted hazard ratio = 2.66, 95% CI: 1.50-3.76, P = 0.021), and high TBRmax (adjusted hazard ratio = 2.11, 95% CI: 1.24-3.74) were independent risk factors for OS.

Conclusion: SUVmax and TBRmax derived from 18F-FDG PET/CT serve as independent predictors of OS in patients with glioma. When integrated with conventional prognostic markers (e.g. WHO grade and IDH mutation status), these metabolic parameters provide critical insights for risk stratification and personalized therapeutic decision-making.

Objective: To investigate the influence of different feature aggregation and selection methods on the predictive performance of fluorine-18 fluorodeoxyglucose (18F-FDG) PET radiomics in assessing survival outcomes in patients with lymphoma.

Methods: This retrospective analysis included 80 patients with histologically confirmed lymphoma, each presenting with at least three lesions on baseline 18F-FDG PET images. Metabolic tumor volumes were segmented using a standardized uptake value threshold of 4.0. From each lesion, 107 radiomic features were extracted. Of these, 30 features were preselected based on their robustness to variations in tracer uptake time, image reconstruction parameters, and respiratory motion. Six distinct feature aggregation approaches were evaluated in combination with six feature selection methods. Multivariable Cox proportional hazards regression was used to assess the predictive performance of each aggregation-selection strategy for progression-free survival (PFS) and overall survival (OS).

Results: All combinations of feature aggregation and selection methods produced statistically significant prognostic models for PFS and OS, with Harrell's concordance indices (C-index) ranging from 0.582 to 0.668 for PFS and from 0.597 to 0.721 for OS. The best predictive performance was achieved using median value aggregation across all individual lesions combined with feature selection via the least absolute shrinkage and selection operator. Integrating clinical variables with radiomic features further improved predictive performance.

Conclusion: The prognostic value of 18F-FDG PET radiomics remained consistent across different feature aggregation and selection strategies. The establishment of standardized analysis workflows is essential to facilitate its clinical implementation in personalized treatment planning for patients with lymphoma.

Objective: To evaluate the therapeutic efficacy and safety of intrathoracic administration of 90Y-labeled anti-podoplanin antibody NZ-16 in a pleural mesothelioma murine model, in comparison with conventional intravenous administration.

Materials and methods: An intrathoracic mesothelioma model was established using H226-Luc cells in nude mice. Biodistribution and dosimetry were assessed using 111In-labeled NZ-16. Mice received either intravenous or intrathoracic administration of 90Y-labeled NZ-16 (3.7 or 7.4 MBq). Tumor growth, survival duration, hematologic toxicity, and histological changes were evaluated.

Results: Intrathoracic administration resulted in 1.3-fold higher tumor uptake and reduced accumulation in normal organs compared with intravenous administration. Dosimetric analysis showed lower absorbed doses in bone marrow and lungs with intrathoracic delivery. At 3.7 MBq, intrathoracic administration significantly improved tumor regression and survival compared with the intravenous route. Histological analysis revealed enhanced fibrosis in intrathoracic-treated tumors. Hematologic toxicity was milder with intrathoracic administration.

Conclusion: Intrathoracic administration of 90Y-labeled NZ-16 may offer improved therapeutic efficacy and reduced systemic toxicity compared with intravenous administration in pleural mesothelioma. These findings suggest that intrathoracic delivery could be a promising approach for enhancing treatment outcomes in patients with unresectable disease.

Aims: To determine the diagnostic performance and clinical usefulness of 18F-fluorodeoxyglucose (18F-FDG) PET computerised tomography (CT) in detecting cardiac inflammation in patients with suspected cardiac sarcoidosis; and to explore the role of interval and correlative imaging.

Material and methods: A 10-year (2015-2024) retrospective observational study was conducted at our teaching hospital. 397 18F-FDG PET-CT scans performed in 296 patients with suspected or known cardiac sarcoidosis were reviewed. Assessment of diagnostic quality, patterns of myocardial and extracardiac FDG uptake, concordance with other modalities [cardiac MRI (CMR) and myocardial perfusion imaging (MPI)] were assessed. Separate subgroup analysis of patients undergoing repeat 18F-FDG PET-CT scans was conducted.

Results: Images of excellent diagnostic quality 18F-FDG PET-CT were obtained in 365/397 studies (91.9%). Cardiac inflammation was identified in 226 and scans were normal in 139 patients. Extracardiac sarcoidosis was present in 230 (63%) patients. MPI was abnormal in 50/98 patients (51%) and CMR was abnormal in 88/126 patients (70%). PET and MPI findings showed concordance in 53% patients but not considered significant (P = 0.78). High concordance with CMR was noted in 85.7% patients (P < 0.001). For treatment monitoring, follow-up 18F-FDG PET-CT scans accurately assessed disease status in 66/70 patients (94.2%).

Conclusion: We obtained excellent diagnostic quality of images in a high proportion of our patients (92%). Because of a high degree of concordance between 18F-FDG PET-CT and CMR, we propose that either test can be used initially and the other test can be used in cases of clinical discordance. Interval 18F-FDG PET-CT scans are immensely useful for treatment response monitoring.

Purpose: 177Lu-DOTATATE-targeted radionuclide therapy (TRT) is effective for patients with somatostatin receptor (SSTR)-positive neuroendocrine tumors; however, radiation safety regulations often necessitate hospitalization, particularly in countries with stringent discharge criteria. This study aimed to identify pretreatment factors predicting outpatient eligibility.

Methods: We retrospectively analyzed 26 patients who underwent their first cycle of 177Lu-DOTATATE TRT with complete data for analysis. The external dose rate at 1 m (EDR-1 m) was measured 6 h after administration. Patients were divided into two groups: EDR-1 m greater than or equal to 18 μSv/h and less than 18 μSv/h. Characteristics, including age, sex, BMI, body surface area, estimated glomerular filtration rate, administered dose, and tumor site, were compared. In addition, the whole-body washout rate from pretreatment SSTR imaging was evaluated as a potential predictor. Logistic regression and receiver operating characteristic (ROC) analyses were conducted.

Results: Fourteen of the 26 (53.8%) patients met the discharge criterion at 6 h. No significant differences were observed in demographic or clinical characteristics between groups. The median washout rate was significantly higher in those meeting the criterion (57.6 vs. 35.0%; P < 0.001). The area under the ROC curve for the washout rate was 0.929, indicating excellent predictive ability. An optimal cut-off value of 53.5% predicted same-day discharge with a sensitivity of 92.9% and specificity of 91.7%.

Conclusion: The whole-body washout rate derived from pretreatment SSTR imaging is a strong, practical predictor for outpatient eligibility following 177Lu-DOTATATE TRT. Incorporating this simple, noninvasive marker into clinical workflow could support individualized discharge planning and improve patient access under strict radiation safety regulations.

Objective: The aim of this retrospective study is to evaluate the diagnostic accuracy of [68Ga]Ga-Trivehexin PET/CT compared with [18F]fluorodeoxyglucose (FDG) PET/computed tomography (CT) for nodal staging in various solid tumors.

Materials and methods: Between 2024 and 2025, a total of 15 patients with histopathologically confirmed primary or recurrent cancer were enrolled in the study. All participants underwent both [18F]FDG and [68Ga]Ga-Trivehexin PET/CT imaging for oncologic staging. Imaging findings were compared with histopathological results and clinical/radiological follow-up. Primary tumors, lymph nodes, and metastases were visually assessed, and maximum standardized uptake values were calculated.

Results: The median age of the patients was 62 years. Diagnoses included colorectal, breast, pancreatic, lung, bladder, thyroid, and endometrial cancers. Both [18F]FDG and [68Ga]Ga-Trivehexin PET/CT demonstrated uptake in all primary tumors. While [18F]FDG PET/CT showed uptake in all lymph nodes, [68Ga]Ga-Trivehexin PET/CT demonstrated positive uptake only in metastatic lymph nodes. The positive predictive value of [68Ga]Ga-Trivehexin PET/CT was calculated as 100%. In contrast, [18F]FDG PET/CT exhibited lower specificity, with a positive predictive value of 26.3%.

Conclusion: This study demonstrates that [68Ga]Ga-Trivehexin PET/CT offers higher specificity than [18F]FDG PET/CT, particularly in benign lymph node lesions, and is effective in accurately identifying metastatic lymph nodes. Compared to [18F]FDG PET/CT, 68Ga-Trivehexin PET/CT provides lower false-positive rates and higher diagnostic accuracy, potentially reducing the need for unnecessary invasive procedures.

Objectives: To investigate the differences fluorodeoxyglucose (FDG) dynamics between clear cell renal cell carcinoma (ccRCC) and non-ccRCC as a potential diagnostic clue, using dynamic whole-body (D-WB) and dual-time-point (DTP) FDG-PET/computed tomography (CT) imaging.

Patients and methods: D-WB and DTP FDG-PET/CT scans were performed for 26 RCC patients. We obtained Pearson's correlation coefficients between the static [maximum standardized uptake value (SUVmax) and tumor size] and dynamic [metabolic rate (MRFDG) and distribution volume of FDG (DVFDG)] parameters. We compared MRFDG and DVFDG by tumor type and performed receiver operating characteristic (ROC) analyses for each parameter.

Results: Nineteen ccRCC and nine non-ccRCC lesions including molecularly defined carcinomas were analyzed. Compared with the ccRCC (r = 0.55-0.81), the MRFDG in the non-ccRCC was more strongly correlated with the early (SUVe) and delayed (SUVd) SUVmax and tumor size (r = 0.72-0.97). The DVFDG in the non-ccRCC was more strongly correlated with SUVe and SUVd (r = 0.93, 0.84) vs. the ccRCC (r = 0.55, 0.66). SUVe and SUVd were significantly higher in the non-ccRCC vs. ccRCC (analyses for all or T3/4 RCC, both P < 0.05). MRFDG was significantly higher in the T3/4 non-ccRCC vs. the T3/4 ccRCC (P = 0.04). In the ROC analysis for differentiating ccRCC and non-ccRCC, SUVd showed the highest area under the curve (0.92-0.93 for all and T3/4 RCC) than other parameters (0.70-0.84).

Conclusion: D-WB FDG-PET/CT imaging clearly demonstrated different FDG dynamics between ccRCC and non-ccRCC. Non-ccRCC showed higher MRFDG values than ccRCC, but dynamic images have a limited role in differentiating these lesions. SUVd could be the most suitable parameter for differentiating ccRCC and non-ccRCC.