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18 F-FDG PET/CT quantification of whole-body tumor burden in lymphoma is not routinely performed because of the lack of fast methods. Although the semiautomatic method is fast, it is not fast enough to quantify tumor burden in daily clinical practice. Our purpose was to evaluate the performance of convolutional neural network (CNN) software in localizing neoplastic lesions in whole-body 18 F-FDG PET/CT images of pediatric lymphoma patients. Methods: The retrospective image dataset, derived from the data pool of the International Atomic Energy Agency (coordinated research project E12017), included 102 baseline staging 18 F-FDG PET/CT studies of pediatric lymphoma patients (mean age, 11 y). The images were quantified to determine the whole-body tumor burden (whole-body metabolic tumor volume [wbMTV] and whole-body total lesion glycolysis [wbTLG]) using semiautomatic software and CNN-based software. Both were displayed as semiautomatic wbMTV and wbTLG and as CNN wbMTV and wbTLG. The intraclass correlation coefficient (ICC) was applied to evaluate concordance between the CNN-based software and the semiautomatic software. Results: Twenty-six patients were excluded from the analysis because the software was unable to perform calculations for them. In the remaining 76 patients, CNN and semiautomatic wbMTV tumor burden metrics correlated strongly (ICC, 0.993; 95% CI, 0.989 - 0.996; P < 0.0001), as did CNN and semiautomatic wbTLG (ICC, 0.999; 95% CI, 0.998-0.999; P < 0.0001). However, the time spent calculating these metrics was significantly (<0.0001) less by CNN (mean, 19 s; range, 11-50 s) than by the semiautomatic method (mean, 21.6 min; range, 3.2-62.1 min), especially in patients with advanced disease. Conclusion: Determining whole-body tumor burden in pediatric lymphoma patients using CNN is fast and feasible in clinical practice., (© 2022 by the Society of Nuclear Medicine and Molecular Imaging.)

Biochemical recurrence (BCR) is a clinical challenge in prostate cancer (PCa) patients, as recurrence localization guides subsequent therapies. The use of PET with prostate-specific membrane antigen (PSMA) provides better accuracy than conventional imaging practice. This prospective, multicenter, international study was performed to evaluate the diagnostic performance and clinical impact of PSMA PET/CT for evaluating BCR in PCa patients in a worldwide scenario. Methods: Patients were recruited from 17 centers in 15 countries. Inclusion criteria were histopathologically proven prostate adenocarcinoma, previous primary treatment, clinically established BCR, and negative conventional imaging (CT plus bone scintigraphy) and MRI results for patients with PSA levels of 4-10 ng/mL. All patients underwent PET/CT scanning with 68 Ga-PSMA-11. Images and data were centrally reviewed. Multivariate logistic regression analysis was applied to identify the independent predictors of PSMA-positive results. Variables were selected for this regression model on the basis of significant associations in the univariate analysis and previous clinical knowledge: Gleason score, the PSA level at the time of the PET scan, PSA doubling time, and primary treatment strategy. All patients were monitored for a minimum of 6 mo. Results: From a total of 1,004 patients, 77.7% were treated initially with radical prostatectomy and 22.3% were treated with radiotherapy. Overall, 65.1% had positive PSMA PET/CT results. PSMA PET/CT positivity was correlated with the Gleason score, PSA level at the time of the PET scan, PSA doubling time, and radiotherapy as the primary treatment ( P < 0.001). Treatment was modified on the basis of PSMA PET/CT results in 56.8% of patients. PSMA PET/CT positivity rates were consistent and not statistically different among countries with different incomes. Conclusion: This multicenter, international, prospective trial of PSMA PET/CT confirmed its capability for detecting local and metastatic recurrence in most PCa patients in the setting of BCR. PSMA PET/CT positivity was correlated with the Gleason score, PSA level at the time of the PET scan, PSA doubling time, and radiotherapy as the primary treatment. PSMA PET/CT results led to changes in therapeutic management in more than half of the cohort. The study demonstrated the reliability and worldwide feasibility of PSMA PET/CT in the workup of PCa patients with BCR., (© 2022 by the Society of Nuclear Medicine and Molecular Imaging.)

Guidelines recommend true whole-body 18 F-FDG PET/CT scans from vertex to toes in pediatric lymphoma patients, although this suggestion has not been validated in large clinical trials. The objective of the study was to evaluate the incidence and clinical impact of lesions outside the "eyes to thighs" regular field of view (R-FOV) in 18 F-FDG PET/CT staging (sPET) and interim (iPET) scans in pediatric lymphoma patients. Methods: True whole-body sPET and iPET scans were prospectively obtained in pediatric lymphoma patients (11 worldwide centers). Expert panel central review of sPET and iPET scans were evaluated for lymphoma lesions outside the R-FOV and clinical relevance of these findings. Results: A total of 610 scans were obtained in 305 patients. The sPET scans did not show lesions outside the R-FOV in 91.8% of the patients, whereas in 8.2% patients the sPET scans demonstrated lesions also outside the R-FOV (soft tissue, bone, bone marrow, and skin); however, the presence of these lesions did not change the clinical stage of any patient and did not affect treatment decision. Among the 305 iPET scans, there were no new positive 18 F-FDG-avid lesions outside the R-FOV, when compared with their paired sPET scans. A single lesion outside the R-FOV on iPET occurred in 1 patient (0.3%), with the primary lesion diagnosed in the femur on sPET that persisted on iPET. Conclusion: The identification of additional lesions outside the R-FOV (eyes to thighs) using 18 F-FDG PET/CT has no impact in the definition of the clinical stage of disease and minimal impact in the treatment definition of patients with pediatric lymphoma. As so, R-FOV for both sPET and iPET scans could be performed., (© 2019 by the Society of Nuclear Medicine and Molecular Imaging.)

Unlabelled: Most first relapses in patients with melanoma occur in regional lymph node basins. Such lesions are frequently diagnosed clinically during the first 2 y of follow-up. In the last few years, our group has been studying the usefulness of (99m)Tc-methoxyisobutylisonitrile (MIBI) scintigraphy in the evaluation of recurrent melanoma lesions. The aim of the present study was to prospectively evaluate the clinical value of (99m)Tc-MIBI scintigraphy in the diagnosis of subclinical nodal metastases., Methods: We included 66 patients within 3 mo of melanoma diagnosis, with Breslow thickness > 1.0 mm, all treated with wide local excision of the primary lesion. When (99m)Tc-MIBI scanning was performed, 49 of them did not have evidence of nodal disease, and 17 had clinically questionable regional lymph node lesions. Planar images of lymph node regions were acquired 10 min after injection, using a dose of 740-1,110 MBq and a large-field-of-view gamma camera equipped with a low-energy high-resolution collimator. Scan findings were confirmed by pathology or by clinical follow-up (median, 35 mo)., Results: Thirty of 33 patients with regional lymph node metastases received a correct diagnosis, 14 with palpable lesions and 16 with nonpalpable lesions. In 3 cases that were initially (99m)Tc-MIBI negative, nodal metastases were found during follow-up. The following diagnostic values were calculated: sensitivity, 0.91 (95% confidence interval [CI], 0.75-0.98); specificity, 0.85 (95% CI, 0.67-0.94); likelihood ratio of a positive test, 6.0 (95% CI, 2.7-13.5); and likelihood ratio of a negative test, 0.11 (95% CI, 0.036-0.32)., Conclusion: (99m)Tc-MIBI scanning may have a secondary role in the staging of regional lymph nodes in patients with clinically localized melanoma who are not good candidates for sentinel node biopsy.

Unlabelled: Different radiopharmaceuticals have been used to detect breast cancer. Among them, sestamibi has been extensively studied and has come to have a well-recognized role in the evaluation of palpable breast lesions. The goal of this study was to compare the diagnostic value of 99mTc-labeled compounds, such as methylene diphosphonate (MDP) and pentavalent dimercaptosuccinic acid (DMSA-V), with sestamibi for palpable breast lesions, in the scope of a multicenter trial sponsored by the International Atomic Energy Agency., Methods: Patients from 7 countries were included: 47 women (mean age, 54 +/- 13 y) examined with MDP and sestamibi and 111 women (mean age, 55 +/- 12 y) examined with DMSA-V and sestamibi. Cancer was diagnosed in 41 of 49 lesions from the MDP group and in 78 of 113 lesions from the DMSA-V group. Axillary lymph node involvement was observed in 18 of 30 patients from the first group and in 27 of 53 patients from the second group. Prone scintimammography was performed using a dose of 740 MBq of each tracer, and diagnostic values were calculated from a masked interpretation of scans., Results: In the first group, the sensitivity for sestamibi and MDP studies was 82.9% and 65.9%, respectively, with a specificity of 87.5% and 50%, respectively. In the second group, the sensitivity for sestamibi and DMSA-V studies was 87.2% and 65.4%, respectively, with a specificity of 77.1% and 74.3%, respectively. Regarding axillary involvement, the sensitivity was 33.3% for sestamibi in both groups, whereas the values for MDP and DMSA-V were 16.7% and 7.4%, respectively. In contrast, the specificity for sestamibi was 83.3% and 92.3% for the first and second groups, respectively, and the specificity for MDP and DMSA-V was 91.7% and 100%, respectively., Conclusion: Sestamibi is the most adequate alternative among the mentioned 99mTc-labeled radiopharmaceuticals for the evaluation of palpable breast lesions.

Unlabelled: The aim of this trial was to evaluate in developing countries from different regions the diagnostic performance of (99m)Tc-sestamibi scintimammography (SM) in palpable breast lesions and to verify the clinical usefulness of a joint evaluation with mammography and SM., Methods: From 10 countries, a total of 238 patients with palpable breast masses (n = 245) were included in this prospective multicenter trial. Prone SM was performed 10 min and 60-90 min (157 patients) after injection using an isotime acquisition of 10 min. Mammography was assessed by the same dedicated imaging radiologist according to breast imaging reporting and data system (BI-RADS) categories for malignancy and breast density. Masked SM findings and mammography findings were checked for a correlation with histopathology findings for excisional biopsy samples. Diagnostic values for breast cancer detection were calculated per lesion., Results: Histopathology revealed 189 cancerous lesions and 56 benign lesions. The sensitivity and specificity of SM were 0.83 and 0.77, respectively. SM diagnostic values did not depend on the incidence of breast cancer in the country of origin or on the timing of imaging (early vs. delayed scans). On mammography, the technique yielded a sensitivity and specificity of 0.85 and 0.66, with 27 mammograms classified as BI-RADS category 1, 33 as category 2, 5 as category 3, 56 as category 4, and 124 as category 5. Thirty-seven lesions were considered to show increased radiologic density. No significant difference was found in SM diagnostic values among different BI-RADS categories or between the groups with low and high breast density. A sensitivity of 96% was calculated when SM and mammography results were combined, with 75% of all false-negative mammography findings classified as true-positive results by SM., Conclusion: SM complements mammography in patients with palpable masses and negative mammography findings.