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Objectives: This study aims to decrease the scan time and enhance image quality in pediatric total-body PET imaging by utilizing multimodal artificial intelligence techniques. Methods: A total of 270 pediatric patients who underwent total-body PET/CT scans with a uEXPLORER at the Sun Yat-sen University Cancer Center were retrospectively enrolled. 18F-fluorodeoxyglucose (18F-FDG) was administered at a dose of 3.7 MBq/kg with an acquisition time of 600 s. Short-term scan PET images (acquired within 6, 15, 30, 60 and 150 s) were obtained by truncating the list-mode data. A three-dimensional (3D) neural network was developed with a residual network as the basic structure, fusing low-dose CT images as prior information, which were fed to the network at different scales. The short-term PET images and low-dose CT images were processed by the multimodal 3D network to generate full-length, high-dose PET images. The nonlocal means method and the same 3D network without the fused CT information were used as reference methods. The performance of the network model was evaluated by quantitative and qualitative analyses. Results: Multimodal artificial intelligence techniques can significantly improve PET image quality. When fused with prior CT information, the anatomical information of the images was enhanced, and 60 s of scan data produced images of quality comparable to that of the full-time data. Conclusion: Multimodal artificial intelligence techniques can effectively improve the quality of pediatric total-body PET/CT images acquired using ultrashort scan times. This has the potential to decrease the use of sedation, enhance guardian confidence, and reduce the probability of motion artifacts. [ABSTRACT FROM AUTHOR]

Objectives: To compare the diagnostic and staging efficacy of PET/diagnostic-level CT (PET/DxCT) and PET/low-dose CT (PET/LDCT) in pretreatment pediatric lymphoma patients and to estimate the reduction of the CT effective dose in the PET/CT scan. Methods: One hundred and five pediatric patients who underwent total-body PET/CT examination were enrolled and divided into the DxCT group (n = 47) and LDCT group (n = 58) according to their dose levels. The sensitivity, specificity, PPV, and NPV of PET/DxCT and PET/LDCT for detecting the involvement of lymph node, spleen, bone marrow, and other extranodal organs in pretreatment lymphoma were compared. ROC analysis was performed to evaluate the integral efficiency. The staging accuracies based on PET/DxCT and PET/LDCT were also evaluated. Dosimetry was calculated for DxCT and LDCT, and the reduction in the effective dose was estimated. Results: In the diagnosis of nodal, splenic, bone marrow, and other extranodal involvement, the differences in sensitivity, specificity, PPV, and NPV between PET/LDCT and PET/DxCT were not significant (all p values ∈ [0.332, 1.000]). Both modalities had accuracies above 90% and the ROC analysis indicated good or high efficiency in diagnosing all patterns of lymphoma involvement. PET/LDCT and PET/DxCT each had a staging accuracy of 89.7% and 89.4%, respectively. LDCT had a comparable image quality score with DxCT, with a significant increase in noise (p < 0.001) and a 66.1% reduction in effective dose. Conclusions: PET/LDCT allowed for a 66.1% CT effective dose reduction compared to PET/DxCT in pediatric lymphoma patients without compromising the diagnostic and staging efficacy. Key Points: • Pediatric lymphoma patients can benefit from a reduced effective dose of PET/CT. • This retrospective study showed that the diagnostic and staging efficacies of PET/low-dose CT are comparable to those of PET/diagnostic-level CT, both with satisfactory efficiency in diagnosing all patterns of lymphoma involvement. • PET/low-dose CT allowed for a 66.1% CT effective dose reduction compared to PET/diagnostic-level CT. [ABSTRACT FROM AUTHOR]