Nuclear Medicine Communications最新文献

Background: Nuclear medicine's lung perfusion scintigraphy is a valuable imaging technique for assessing many health conditions. Various methods have been described in the literature for segmenting and quantifying the lung perfusion in single-photon emission computed tomography/computed tomography (SPECT/CT) images, but they rely on commercially available software, require manual definition of regions/volumes of interest, or both.

Objective: This study proposes a never reported approach to segment and quantify SPECT (and SPECT/CT) lung perfusion images by developing a fully automated algorithm utilizing only free software.

Methods: Python programming language was used to write a completely automated algorithm for 3D Slicer to segment and quantify SPECT and SPECT/CT images. The algorithm was tested in 37 lung perfusion images, collected retrospectively from a public hospital database.

Results: The algorithm was able to perform fully automated lobar perfusion quantification. The mean relative perfusion found were: LUL - 23.5%, LLL - 22.3%, RUL - 24.6%, RML - 7.9%, and RLL - 21.7%. The algorithm also segmented and quantified the relative perfusion of the left (L) and right (R) lungs without the aid of CT: L - 44.6% and R - 55.3%; and found no statistical difference in the results obtained with or without CT ( P -value = 0.38 and 0.44, respectively).

Conclusion: The algorithm created required no user interaction, presented good agreement with previously reported works, and was on average 10 times faster than the fastest algorithm reported on the literature, thus making it a free, efficient, and reliable tool for assisting diagnosis.

Objective: The aim of this retrospective study is to evaluate the diagnostic accuracy of [ 68 Ga]Ga-Trivehexin PET/CT compared with [ 18 F]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 [ 18 F]FDG and [ 68 Ga]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 [ 18 F]FDG and [ 68 Ga]Ga-Trivehexin PET/CT demonstrated uptake in all primary tumors. While [ 18 F]FDG PET/CT showed uptake in all lymph nodes, [ 68 Ga]Ga-Trivehexin PET/CT demonstrated positive uptake only in metastatic lymph nodes. The positive predictive value of [ 68 Ga]Ga-Trivehexin PET/CT was calculated as 100%. In contrast, [ 18 F]FDG PET/CT exhibited lower specificity, with a positive predictive value of 26.3%.

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

Nasopharyngeal carcinoma is a highly aggressive malignant tumor, and research into its immunotherapy has attracted considerable attention in recent years. Imaging assessment plays a pivotal role in monitoring the efficacy of immunotherapy. Traditional evaluation methods are becoming increasingly limited in clinical applicability because of their inability to capture the spatiotemporal heterogeneity of immunotherapy responses. In this context, the development of multimodal fusion imaging techniques, radiomics, and novel probes offers new perspectives to address these challenges. These advanced and emerging technologies not only provide more comprehensive and precise anatomical, functional, and metabolic information but also enable multidimensional and in-depth data mining and analysis, thereby optimizing immunotherapy response evaluation workflows and enhancing the accuracy of efficacy predictions. Future research should focus on establishing and standardizing novel assessment systems, developing and optimizing specific molecular probes, and integrating multiomics data to advance personalized therapeutic decision-making. This narrative review retrospectively summarizes the progress in imaging assessment for nasopharyngeal carcinoma immunotherapy, spanning from the limitations of conventional methods to the application of technological innovations, and ultimately identifying optimized pathways for clinical practice, with the goal of providing a reference for future research.

Objective: Imaging vertebral molecular activity with PET/computed tomography (CT) may enable earlier detection of degenerative diseases of the spine. This study aimed to evaluate physiological patterns of vertebral molecular activity and their association with degenerative risk factors with 18F-fluorodeoxyglucose (18F-FDG) and 18F-sodium fluoride (18F-NaF) PET/CT.

Methods: 120 subjects (mean age 48.8 ± 14.1 years, 51% male) underwent 18F-FDG and 18F-NaF PET/CT imaging. The TotalSegmentator software was used to automatically generate regions of interest surrounding each vertebral body to quantify mean standardized uptake value (SUVmean) for each radiotracer, average Hounsfield Units, and volume.

Results: Cervical and lumbar 18F-FDG SUVmean exceeded thoracic uptake (P < 0.01). 18F-NaF activity was greatest in the lumbar spine, followed by the thoracic and the cervical regions (P < 0.01). 18F-FDG SUVmean was associated with age (ρ = 0.19, P = 0.03, cervical), BMI (ρ = 0.28-0.40, P < 0.01, all regions), bone density (ρ = -0.30, P = 0.01, cervical), and volume (ρ = -0.20, P = 0.02, cervical). 18F-NaF SUVmean correlated with age (ρ = 0.21 and -0.20, P ≤ 0.03 in cervical and lumbar regions, respectively), BMI (ρ = 0.23 and 0.26, P ≤ 0.01in thoracic and lumbar regions, respectively), bone density (ρ = 0.38, P < 0.01, lumbar), and volume (ρ = -0.30, P < 0.01, lumbar). Cervical 18F-FDG and 18F-NaF SUVmean were higher in females than males.

Conclusion: 18F-FDG and 18F-NaF PET/CT reveal distinct physiological patterns of vertebral molecular activity associated with degenerative risk factors, which may improve screening and prognostic methods for vertebral pathology.

Aim: Quantitative single-photon emission computed tomography (SPECT) with 99m Tc-3,3-diphosphono-1,2 propanodicarboxylicacid ([ 99m Tc]Tc-DPD) is a cornerstone in the noninvasive diagnostic workup of amyloid transthyretin-related cardiomyopathy (ATTR-CM). As diagnosis is often suspected after transthoracic echocardiography (TTE), this study aims to explore the correlations between global and regional quantitative [ 99m Tc]Tc-DPD SPECT results and TTE findings in patients with suspected ATTR-CM.

Methods: Patients with suspected ATTR-CM from a single-center registry (B-CARE) were retrospectively included. All underwent quantitative [ 99m Tc]Tc-DPD SPECT/CT at the baseline examination with calculation of standardized values [maximum standardized uptake value (SUV max ) and peak SUV (SUV peak )], also normalized to bone activity (nSUV max and nSUV peak ). Data on TTE, performed within 2 weeks from the DPD scintigraphy, were also collected.

Results: One hundred forty four patients were included. Of these, 99 patients were eventually diagnosed with ATTR-CM. There was a significant correlation between septal ( P  ≤ 0.001) and lateral wall thickness ( P  = 0.004) and their respective, regional SUVs ( P  < 0.001 and P  = 0.004, respectively), as well as global SUVs and maximum wall thickness ( P  = 0.024). Also, the presence of severe diastolic dysfunction correlated with nSUVs ( P  = 0.011).

Conclusion: The robust correlation found between TTE-derived parameters and the corresponding [ 99m Tc]Tc-DPD SPECT SUVs supports the link between morphologic alterations and [ 99m Tc]Tc-DPD activity within the myocardium, also potentially highlighting a pathophysiological mechanism involved in the progression of ATTR-CM.

Objective: To evaluate the clinical significance of volumetric parameters derived from 68Ga-prostate-specific membrane antigen (PSMA) PET/computed tomography (CT) for prostate cancer staging and their association with metastatic disease and tumor aggressiveness.

Methods: This retrospective study included 206 treatment-naive patients with newly diagnosed, histopathologically confirmed prostate cancer who underwent 68Ga-PSMA PET/CT for initial staging. Primary tumor maximum standardized uptake value (SUVmax), SUVmean, PSMA tumor volume (PSMA-TV), and total lesion PSMA (TL-PSMA) were measured using a semi-automatic segmentation method. Metastatic disease was defined by PSMA-avid nodal or distant lesions. Imaging parameters were correlated with serum prostate-specific antigen (PSA) levels, Gleason score, International Society of Urological Pathology (ISUP) grade, and D'Amico risk classification. Diagnostic performance was assessed using receiver operating characteristic analysis, and independent predictors of metastasis were evaluated using multivariable logistic regression.

Results: Metastatic disease was detected in 52 of 206 patients (25.2%). TL-PSMA showed the highest diagnostic performance for predicting metastasis [area under the curve (AUC) = 0.80], followed by PSA (AUC = 0.78) and PSMA-TV (AUC = 0.77), whereas SUV-based parameters demonstrated moderate accuracy (AUC = 0.74). In multivariable analysis, TL-PSMA and PSA remained independent predictors of metastatic disease (both P < 0.01). Volumetric and SUV-based PSMA parameters increased significantly with higher D'Amico risk category, ISUP grade, and Gleason score (all P < 0.0001). Bilobar intraprostatic PSMA uptake was significantly associated with metastatic disease and high-risk pathological features (P < 0.0001).

Conclusion: Volumetric 68Ga-PSMA PET/CT parameters, particularly TL-PSMA, provide clinically relevant information for prostate cancer staging beyond conventional SUV metrics and PSA. Bilobar intraprostatic PSMA uptake is associated with aggressive disease and increased metastatic risk and may serve as a useful imaging marker in initial staging.

Purpose: To evaluate the robustness of the Hopkins criteria score (HCS) with regards to new PET reconstruction methods in therapy response assessment of head and neck cancer after (chemo)radiotherapy [(C)RT].

Methods: Maximum standardized uptake value and HCS were retrospectively assessed on fluorine-18-deoxyglucose PET/computed tomography (CT) 12 weeks after (C)RT for neck lymph nodes and the primary tumor site in 66 patients with three different reconstruction methods: standard high sensitivity reconstruction, European Association of Nuclear Medicine (EANM) Research Ltd. (EARL) reference standards 1 (EARL1) and 2 (EARL2). Histopathology (27 patients, 41%) or follow-up PET/CT 9 months after end of treatment (39 patients, 59%) served as reference standard. HCS 4 and 5 were rated as positive, 1-3 negative. The performance of HCS for all methods and intermethod concordance was assessed.

Results: A total of 17 (26%) patients had tumor persistence. There was no significant difference in the performance of the reconstruction methods regarding tumor persistence. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for PET/CT with HCS for overall tumor persistence was 77, 80, 57, 91, and 79% for sensitivity reconstruction, 65, 90, 69, 88, and 83% for EARL1 and 71, 82, 57, 89, and 79% for EARL2. The intermethod concordance of HCS across all sites demonstrated a substantial to perfect agreement with Cohens κ ranging from 0.6 to 1.0.

Conclusion: PET/CT HCS for therapy response assessment in head and neck cancer serves as a robust Score independent of newer sensitive reconstructions. Despite the high NPV of PET/CT in this situation the unsatisfactory PPV remains challenging.

Background: Gliomas remain challenging because of their heterogeneity and poor prognosis. This study evaluated the prognostic value of metabolic parameters derived from L-methyl-11C-methionine (11C-MET) PET/computed tomography (CT) performed before adjuvant therapy in glioma patients.

Methods: A retrospective analysis was conducted on 22 postoperative glioma patients who underwent 11C-MET PET/CT before initiating adjuvant therapy. Metabolic parameters, including maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), metabolic tumor volume (MTV), total lesion glycolysis (TLG), maximum tumor-to-brain ratio (TBRmax), and mean tumor-to-brain ratio (TBRmean) were extracted, calculated, and analyzed. Receiver operating characteristic analyses were performed to determine optimal cut-off values for predicting progression-free survival (PFS). Kaplan-Meier and log-rank tests were used to evaluate the relationship between metabolic parameters and PFS.

Results: All six parameters significantly predicted PFS. Optimal thresholds were SUVmax (3.03), area under the curve (AUC): 0.884, SUVmean (2.84), AUC: 0.942, MTV (0.641, AUC: 0.880), TLG (2.140, AUC: 0.860), TBRmax (4.64, AUC: 0.760), and TBRmean (4.50, AUC: 0.851). Patients above these cutoffs had shorter PFS (all P < 0.05). In the high-uptake groups (defined by thresholds: SUVmax > 3.03, SUVmean > 2.84, MTV > 0.641, TLG > 2.140, TBRmax > 4.64), the median overall survival times ranged from 263 to 279 days. In contrast, the low-uptake groups exhibited significantly longer median survival, ranging from 361 to 512 days.

Conclusion: Preadjuvant 11C-MET PET/CT provides valuable prognostic information in postoperative glioma patients. Incorporating 11C-MET PET parameters into postoperative risk stratification may guide individualized treatment strategies and optimize clinical outcomes.

Objectives: To gauge the views of UK nuclear medicine staff on a skin contamination incident of 500 mSv from Tc-99m and Ra-223 (an alpha source).

Methods: An anonymous questionnaire asked staff their concerns on anxiety, erythema, and skin cancer. Also, aspects of removal from open-source work. The same question set was used for Tc-99m and Ra-223.

Results: Replies were grouped as 37 RPAs, 121 other physicists, 78 technologists/radiographers, and 31 radiopharmacy staff. Scores encompassed 1-10 for all staff groups for questions on 'anxiety', 'erythema', and 'skin cancer'. However all staff groups scored significantly higher for Ra-223 than for Tc-99m. The majority of staff in all groups expected to be removed from open-source work, with timescales up to a year. Many staff indicated they would prefer not to be taken out of work (56% for a Tc-99m incident and 47% for a Ra-223 incident). But, a high proportion of staff wanted to have significant time off (≥3 months).

Conclusion: In practice, there is no risk of erythema and the skin cancer risk is extremely low. This applies to Tc-99m and to Ra-223. Also, the IRR2017 allow for someone who receives an overexposure to continue to work, with modified dose limits and agreement from the appointed doctor. All staff groups need to have a clearer understanding of the risks and implications of receiving this level of skin dose. The high anxiety levels indicate that return to work needs careful communication that it is because of low risks and within the legal framework.