Nuclear Medicine Communications最新文献

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 (SUV max ) and tumor size] and dynamic [metabolic rate (MR FDG ) and distribution volume of FDG (DV FDG )] parameters. We compared MR FDG and DV FDG 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 MR FDG in the non-ccRCC was more strongly correlated with the early (SUVe) and delayed (SUVd) SUV max and tumor size ( r = 0.72-0.97). The DV FDG 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). MR FDG 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 MR FDG 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.

Purpose: To evaluate the relationships between anatomical, functional, and metabolic parameters and distant metastasis in the primary staging of rectal adenocarcinoma.

Methods: Seventy-three patients with rectal adenocarcinoma, who underwent pelvic MRI and whole-body 18 F-FDG PET/MRI for staging, were included. Anatomical [T and N stages, extramural venous invasion (EMVI) and circumferential resection margin (CRM) statuses] and functional parameters [apparent diffusion coefficient (ADC) mean (mm²/sn × 10 -6 )] of primary tumor were recorded from pelvic MRI, and metabolic data (maximum standard uptake value (SUV max ), mean SUV (SUV mean ), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and total lesion quotient (TLQ) were recorded from 18 F-FDG PET/MRI. Quantitative parameters combining functional and metabolic data (SUV max /ADC mean , SUV mean /ADC mean , MTV/ADC mean , TLG/ADC mean , TLQ/ADCmean) were calculated. Distant metastases were recorded via 18 F-FDG PET/MRI. To detect lung nodules, supplementary 18 F-FDG PET/CT scans of the thorax were utilized. Relationship between these parameters and distant metastasis, and their ability to predict for distant metastatic disease, were statistically evaluated.

Results: In the univariate logistic regression analysis, the SUV max (1.04; 1.0-1.08; P  = 0.031), TLG (1.0; 1.0-1.005; P  = 0.044), TLG/ADC mean (8.12; 1.04-63.78; P  = 0.046), and presence of EMVI (4.13; 1.31-12.98; P  = 0.015) (OR; CI; P ) were found to predict distant metastasis. In multivariate regression analysis, SUV max (1.05; 1.0-1.1; P  = 0.023) and the presence of EMVI (6.82; 1.64-28.48; P  = 0.008) were identified as independent predictors for distant metastatic disease (OR; CI; P ). Significant associations were detected between distant lymph node metastasis and T stage and the presence of EMVI, whereas significant associations were detected between the size of distant lymph node metastases and the SUV max , SUV mean , SUV max /ADC mean , and SUV mean /ADC mean ( P  < 0.05). Patients with lung and other organ metastases had significantly greater TLG and TLG/ADC mean values ( P  < 0.05).

Conclusion: 18 F-FDG PET/MRI allows obtaining anatomical, functional, and metabolic parameters related to the primary tumor in a single session and has the potential to predict information regarding tumor behavior, including distant metastatic spread.

Objective: To investigate the influence of different feature aggregation and selection methods on the predictive performance of fluorine-18 fluorodeoxyglucose ( 18 F-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 18 F-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 18 F-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: In 2002 a UK audit was performed by the Nuclear Medicine Software Quality Group of filtered back projection (FBP) software, designed to evaluate the quantitative characteristics of single-photon emission computed tomography (SPECT). Subsequently, the use of FBP has reduced in common practice, with most guidelines now recommending and using iterative reconstruction. This study aimed to audit ordered-subset expectation-maximisation (OSEM) algorithms in clinical use, acting on the same input data.

Methods: A computational phantom was devised to evaluate the effect of sphere diameter, position and activity concentration along with an assessment of uniformity and resolution. Additional sections were implemented to evaluate the recovery in photopoenic areas and of small lesions adjacent to active structures. SPECT projections were created from the phantom and placed in the Digital Imaging and Communications in Medicine (DICOM) structures of acquired data from three SPECT camera manufacturers. Resultant projections were reconstructed via five platforms and quantitative measures from the above sections compared.

Results: Across all measures it was found that there was excellent agreement among platforms offering similar reconstruction methods. One platform was found to not offer the ability to perform a true 'pencil-beam' OSEM reconstruction and results varied with different manufacturer data supplied.

Conclusion: While there are differences in how reconstruction platforms process data from different manufacturers, these differences were generally small, with results from the one wide-beam reconstruction method having the largest variation. It would be advisable that users implementing sensitivity-based quantitative SPECT should derive factors for the various combinations of acquisition and reconstruction platforms at their disposal.

Objective: To evaluate the therapeutic efficacy and safety of intrathoracic administration of 90 Y-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 111 In-labeled NZ-16. Mice received either intravenous or intrathoracic administration of 90 Y-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 90 Y-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 18 F-fluorodeoxyglucose ( 18 F-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 18 F-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 18 F-FDG PET-CT scans was conducted.

Results: Images of excellent diagnostic quality 18 F-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 18 F-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 18 F-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 18 F-FDG PET-CT scans are immensely useful for treatment response monitoring.

Objective: The objective of this study is to evaluate the combined prognostic values of 18 F-fluorodeoxyglucose ( 18 F-FDG) PET and computed tomography (CT)-derived entropy-based heterogeneity features from hybrid PET/CT scanner using machine learning in patients with lung adenocarcinoma undergoing curative surgery.

Methods: Presurgical 18 F-FDG PET/CT from 131 patients with lung adenocarcinoma were divided into training ( n  = 92) and temporal validation ( n  = 39) cohorts. In the training cohort, we integrated entropy-based heterogeneity features from 18 F-FDG PET/CT for disease-free survival (DFS) prediction using machine learning approach. The predictive value of clinical variables and 18 F-FDG PET/CT-based machine learning for DFS was examined using Cox regression analyses, and independent prognosticators were used to develop the survival prediction model. The model was then tested in the temporal validation cohort.

Results: In the training cohort, 18 F-FDG PET/CT-based machine learning, female sex, and pN status independently predicted DFS. The model, incorporating these predictors significantly predicted DFS in the training (hazard ratio = 1.483, P  < 0.001) and validation cohorts (hazard ratio = 1.753, P  < 0.001). This model outperformed traditional staging system in both cohorts (c-indices = 0.717 vs. 0.621 in training; and 0.728 vs. 0.644 in validation). The model also predicted overall survival in both cohorts (hazard ratio = 1.370, P  < 0.001 in training; hazard ratio = 1.574, P  = 0.017 in validation).

Conclusion: Our preliminary results suggest that integrating prognostic values from 18 F-FDG PET and CT-based heterogeneity features with clinical prognosticators is feasible and may support personalized treatment strategies for patients with resectable lung adenocarcinoma.

Objectives: The objective of this study is to evaluate the efficacy of multi-parametric MRI (mpMRI) and prostate-specific membrane antigen (PSMA) PET-computed tomography (CT) in preoperative loco-regional assessment of prostate carcinoma, correlating findings with histopathology.

Materials and methods: This prospective observational study enrolled 44 men (mean age 67.5 years) with suspected localized prostate cancer. All participants underwent mpMRI and PSMA PET-CT scans prior to histopathological confirmation via transrectal ultrasound-guided biopsies or radical prostatectomy. Imaging results were analyzed for sensitivity, specificity, and agreement with histopathology using Cohen's Kappa statistic. Key parameters, such as Prostate Imaging Reporting and Data System (PI-RADS) scores (mpMRI) and maximum standardized uptake (SUVmax) values (PSMA PET-CT), were correlated with Gleason scores.

Results: MpMRI exhibited a sensitivity of 95% and specificity of 50%, while PSMA PET-CT achieved 96.3% sensitivity and 57.1% specificity. MpMRI showed strong agreement with histopathology for tumor site localization (Kappa = 0.760), surpassing PSMA PET-CT (Kappa = 0.651). PSMA PET-CT identified metastases in 27.2% of cases, while mpMRI detected extra-prostatic extension in 50%. Higher PI-RADS scores and SUVmax values were associated with increased Gleason scores, indicating aggressive disease.

Conclusion: Both mpMRI and PSMA PET-CT offer high sensitivity for prostate cancer detection. MpMRI is superior for local staging, while PSMA PET-CT excels in identifying distant metastases. Their combined application enhances diagnostic accuracy and supports improved preoperative risk stratification in prostate carcinoma management.

Objective: Development of companion diagnostics for targeted radionuclide therapy is critical, especially for full-size antibodies with prolonged circulation times. Engineering antibodies to modify their in-vivo pharmacokinetics, such as incorporating neonatal Fc receptor (FcRn)-binding mutations, can potentially enable earlier imaging timing and improved patient stratification. This study aimed to evaluate the impact of FcRn-binding mutations on the in-vitro binding characteristics and in-vivo biodistribution and imaging performance of a CD44v6-targeting full-size antibody, UU-40, labeled with different radionuclides, and to assess its potential as a companion diagnostic.

Methods: The study involved engineering UU-40 with LALA and IAHA mutations, evaluating specific binding, internalization, and affinity using in-vitro cell assays. Biodistribution and imaging studies [PET and single-photon emission computed tomography (SPECT)] were conducted in mice carrying human tumor xenografts in a dual-nuclide setting.

Results: The FcRn mutations (LALA/IAHA) did not affect antibody specificity or affinity, which was target-specific and affinity remained in the subnanomolar range. Biodistribution studies demonstrated that the residualizing radiometal label ( 177 Lu) resulted in higher liver and spleen uptake compared with the nonresidualizing 125 I-label, leading to reduced tumor-to-organ ratios. Tumor uptake was higher in A431 xenografts, with peak accumulation at 24 h postinjection. SPECT and PET imaging confirmed superior contrast at later time points (~24 h) with 125 I-UU-40 LALA/IAHA , while earlier imaging with 68 Ga was hindered by increased nonspecific accumulation.

Conclusion: FcRn-binding mutations in full-size antibodies significantly alter their in-vivo pharmacokinetics without affecting binding affinity or specificity. Introducing these mutations enables earlier imaging time points, enhancing the potential for companion diagnostics in clinical settings.