AI Transformers for Radiation Dose Reduction in Serial Whole-Body PET Scans
Yan-Ran Wang, Liangqiong Qu, Natasha Sheybani, Xiaolong Luo, Jiangshan Wang, K. Elizabeth Hawk, Ashok J. Theruvath, Sergios Gatidis, Xue‐Rong Xiao, Allison Pribnow, Daniel L. Rubin, Heike E. Daldrup‐Link
Abstract
Purpose To develop a deep learning approach that enables ultra-low-dose, 1% of the standard clinical dosage (3 MBq/kg), ultrafast whole-body PET reconstruction in cancer imaging. Materials and Methods In this Health Insurance Portability and Accountability Act–compliant study, serial fluorine 18–labeled fluorodeoxyglucose PET/MRI scans of pediatric patients with lymphoma were retrospectively collected from two cross-continental medical centers between July 2015 and March 2020. Global similarity between baseline and follow-up scans was used to develop Masked-LMCTrans, a longitudinal multimodality coattentional convolutional neural network (CNN) transformer that provides interaction and joint reasoning between serial PET/MRI scans from the same patient. Image quality of the reconstructed ultra-low-dose PET was evaluated in comparison with a simulated standard 1% PET image. The performance of Masked-LMCTrans was compared with that of CNNs with pure convolution operations (classic U-Net family), and the effect of different CNN encoders on feature representation was assessed. Statistical differences in the structural similarity index measure (SSIM), peak signal-to-noise ratio (PSNR), and visual information fidelity (VIF) were assessed by two-sample testing with the Wilcoxon signed rank t test. Results The study included 21 patients (mean age, 15 years ± 7 [SD]; 12 female) in the primary cohort and 10 patients (mean age, 13 years ± 4; six female) in the external test cohort. Masked-LMCTrans–reconstructed follow-up PET images demonstrated significantly less noise and more detailed structure compared with simulated 1% extremely ultra-low-dose PET images. SSIM, PSNR, and VIF were significantly higher for Masked-LMCTrans–reconstructed PET (P < .001), with improvements of 15.8%, 23.4%, and 186%, respectively. Conclusion Masked-LMCTrans achieved high image quality reconstruction of 1% low-dose whole-body PET images. Keywords: Pediatrics, PET, Convolutional Neural Network (CNN), Dose Reduction Supplemental material is available for this article. © RSNA, 2023