부산대학교 도서관

Deep image prior (DIP) has been successfully applied to positron emission tomography (PET) image restoration, enabling represent implicit prior using only convolutional neural network architecture without training dataset, whereas the general supervised approach requires massive low- and high-quality PET image pairs. To answer the increased need for PET imaging with DIP, it is indispensable to improve the performance of the underlying DIP itself. Here, we propose a self-supervised pretraining model to improve the DIP-based PET image denoising performance. Our proposed pretraining model acquires transferable and generalizable visual representations from only unlabeled PET images by restoring various degraded PET images in a self-supervised approach. We evaluated the proposed method using clinical brain PET data with various radioactive tracers ( $^{\mathrm{ 18}}\text{F}$ -florbetapir, $^{\mathrm{ 11}}\text{C}$ -Pittsburgh compound-B, $^{\mathrm{ 18}}\text{F}$ -fluoro-2-deoxy-D-glucose, and $^{\mathrm{ 15}}\text{O}$ -CO2) acquired from different PET scanners. The proposed method using the self-supervised pretraining model achieved robust and the state-of-the-art denoising performance while retaining spatial details and quantification accuracy compared to other unsupervised methods and pretraining model. These results highlight the potential that the proposed method is particularly effective against rare diseases and probes and helps reduce the scan time or the radiotracer dose without affecting the patients.