Nuclear Medicine Communications最新文献

Objectives: Differentiated thyroid carcinoma (DTC) frequently metastasizes to lymph nodes, significantly influencing patient prognosis. Posttherapy I-131 whole-body scan with SPECT/computed tomography (CT) (Rx-WBS) is crucial in detecting residual metastatic lymph nodes (reLNs). This study aimed to construct spatial heatmaps of reLNs based on the Rx-WBS to visualize anatomical distribution and to provide references for optimizing lymph node dissection (LND) strategies.

Methods: This retrospective study included 110 intermediate- to high-risk DTC patients who underwent thyroidectomy and LND, followed by I-131 therapy within 3 months postoperatively. reLNs were manually identified and segmented on Rx-WBS using ITK-SNAP. All reLNs were registered onto a reference patient's CT image based on anatomical landmarks. Representative axial and sagittal heatmaps were generated to illustrate the reLNs' spatial patterns. Univariate analysis and multivariable negative binomial regression were used to identify the factors associated with reLNs.

Results: A total of 276 reLNs from 110 patients were mapped to the reference CT. Heatmaps demonstrated that reLNs were most concentrated in level Ⅵ (39.5%), followed by levels Ⅳ (19.2%) and Ⅲ (17.0%), clustering around the internal carotid artery and jugular vein. Levels I, Ⅴ, and the retropharyngeal space showed lower involvement. Univariate analysis revealed that age and the extent of LND were potential influencing factors.

Conclusion: This study constructed anatomical heatmaps of reLNs, revealing spatial 'hotspots' of residual metastases. These visualizations illustrate the anatomical distribution of reLNs and may assist in refining LND strategies.

Background: To analyze the uptake patterns of dual-nuclide PET using 2-[ 18 F]-fluoro-2-deoxy- D -glucose (FDG) and O-(2-[ 18 F]-fluoroethyl)- L -tyrosine (FET) in intracranial lesions.

Methods: This study was conducted from July 2023 to September 2024. Patients with intracranial lesions underwent FDG PET and FET-PET scans on separate days before surgery. Four uptake patterns were observed: type A, positive uptake of both FET and FDG; type B, positive uptake of FET with negative uptake of FDG; type C, negative uptake of FET with positive uptake of FDG; and type D, negative uptake of both FET and FDG. Correlations between standardized uptake values (SUVs) of FET/FDG and tumor proliferation marker Ki-67/tumor protein p53 (P53) were analyzed using Pearson correlation analysis.

Results: Among 28 patients, type A was observed in 17, type B in nine, and type D in two patients. Dual-nuclide PET-based diagnoses were completely consistent with the pathology in nine, partially consistent in 17, and inconsistent in only two patients. Except for mature teratomas, all intracranial tumors demonstrated positive FET uptake. Correlations were observed between FDG and Ki-67: SUV max ( P  = 0.011) and SUV mean ( P  = 0.012). In addition, correlations were observed between the FDG/FET ratio and Ki-67: SUV max ( P  = 0.029) and SUV mean ( P  = 0.021).

Conclusion: Dual-nuclide PET is valuable in diagnosing intracranial lesions. Type A is the most common uptake pattern. The SUV of FDG is positively correlated with the Ki-67 level. Compared with single-modality PET, dual-nuclide PET uptake patterns provide diagnostic insights into intracranial lesions.

Background: Treatment and outcome of soft tissue sarcomas (STS) are presently guided by stage and clinicopathological factors. Radiomics, the quantitative analysis of images applied to [ 18 F]fluoro-2-deoxy- d -glucose (FDG) PET could improve prognostication and thereby treatment outcomes, especially due to its ability to quantify intratumoural metabolic heterogeneity. However, the data for its utility in STS is limited.

Objectives: This study aimed to assess the prognostic value of pretreatment FDG PET-derived radiomic features for patients with STS. A retrospective analysis was performed of patients with STS who underwent FDG PET and were treated with curative intent in a sarcoma centre ( n = 44). Tumour segmentation was performed using a 40% maximum standardised uptake value threshold, and 107 radiomic features were extracted. Univariable and multivariate Cox regression evaluated radiomic features against local recurrence-free survival (LRFS), distant recurrence-free survival (DRFS), disease-free survival (DFS), and overall survival. Survival difference was then assessed using Kaplan-Meier survival curves constructed from receiver operating characteristic (ROC) derived thresholds.

Results: Our study demonstrated measures of tumour heterogeneity predicted outcome, the strongest predictor being, GLSZMSZNUN, which was a significant predictor on multivariate analysis of DRFS [heart rate (HR) = 0.00031, 95% confidence interval (CI) = 2.1 × 10-7-0.45, P = 0.03] and DFS (HR = 0.00047, 95% CI = 1.3 × 10-6-0.16, P = 0.01). Stratification using ROC-derived thresholds showed survival difference for LRFS ( P = 0.045), DRFS ( χ2 = 4.7, P < 0.001), and DFS ( χ2 = 8.1, P = 0.005).

Conclusion: Multiple PET radiomic features demonstrated significant prognostic utility independent of standard clinical features and predicted survival outcomes in STS. Larger prospective multicentre cohorts are required to verify our findings and enable integration into clinical decision aids and precision medicine in STS.

Objective: This study analysed the safety and effectiveness of a 20% dose reduction of 177 Lutetium-labelled prostate-specific membrane antigen (PSMA) radioligand therapy in patients with metastatic castration-resistant prostate carcinoma (mCRPC) and preexisting impaired renal function.

Methods: In this retrospective study, 16 mCRPC patients with impaired renal function - estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m 2 who received 177 Lu-PSMA-I&T were identified. Median number of cycles was 4 (range 1-8 cycles), and median interval between cycles was 6 weeks. Renal function was monitored throughout the treatment. Therapy response was assessed via prostate-specific antigen (PSA) measurements. Patients received a 20% dose reduction from the standard dose of 7.4 GBq. Mean follow-up time was 8.5 months (range 2-37 months). Kaplan-Meier analysis was performed to obtain progression-free survival (PFS) and overall survival (OS).

Results: Mean baseline eGFR was 48 ml/min/1.73 m 2 (range 21-59 ml/min/1.73 m 2 ). Mean end-of-treatment eGFR was 51 ml/min/1.73 m 2 (range 19-83 ml/min/1.73 m 2 ). At the end of follow-up, the mean eGFR was 48 ml/min/1.73 m 2 (range 20-83 ml/min/1.73 m 2 ). There was no evidence that eGFR was affected by the 177 Lu-PSMA-I&T treatment either after the last cycle or at the end of follow-up ( P  > 0.05). No patients suffered grade 4 renal toxicity. After 1 cycle, 50% of patients had a partial PSA response, which increased to 73% after two cycles. Median PFS was 12 months [95% confidence interval (CI): 4-14 months], and OS was 17 months (95% CI: 13-40 months).

Conclusion: Findings support the feasibility of 177 Lu-PSMA-I&T treatment in mCRPC patients with preexisting renal impairment (eGFR 21-59 ml/min/1.73 m 2 ) when a 20% dose reduction is applied.

Objectives: Technetium-99 m ( 99m Tc)-sestamibi, a lipophilic cationic molecule that accumulates in cells rich in mitochondria, can help to characterize the solid renal masses. This study evaluated the accuracy of 99m Tc-sestamibi single photon emission computed tomography/computed tomography (SPECT/CT) in the characterization of solid renal lesions, and we explored whether dynamic imaging could provide added diagnostic value over delayed SPECT/CT in the differentiation of renal lesions into benign and malignant.

Methods: In this prospective study, all referred patients with a solid renal mass who have not undergone any intervention underwent 99m Tc-sestamibi SPECT/CT imaging and, based on lesion (TLsC) to renal background uptake ratio (TRBKG) with a cutoff 0.5, the renal masses were classified as either positive or negative for 99m Tc-sestamibi uptake, and the results compared with final histopathological reports.

Results: Thirty-six patients (28 men and 8 women) were included, of which five patients' renal lesions were 99m Tc-sestamibi positive and 31 were negative. Of the five 99m Tc-sestamibi-positive lesions, four were benign in nature, whereas 30 of 31 99m Tc-sestamibi-negative lesions were malignant. Thus, the sensitivity, specificity, and accuracy of 99m Tc-sestamibi for differentiation of benign and malignant renal lesions were 80% [95% confidence interval (CI), 37.56-96.38], 96.8% (95% CI, 83.81-99.43), and 94.4% (95% CI, 81.86-98.46), respectively. The area under the receiver operating characteristic curve was 0.935 (95% CI 0.84-1.00). Dynamic imaging showed no significant incremental value over delayed 99m Tc-sestamibi SPECT/CT for lesion classification (McNemar's exact P  = 1.00; Fisher's exact P  = 0.163).

Conclusion: The study showed high diagnostic accuracy of 99m Tc-sestamibi SPECT/CT in differentiating benign from malignant solid renal lesions. Its high specificity and negative predictive value make it a potential and valuable noninvasive diagnostic tool for characterizing solid renal lesions, thus guiding further management. Dynamic imaging, however, did not demonstrate incremental diagnostic value over delayed SPECT/CT for characterization of renal lesions.

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.