Deep residual-convolutional neural networks for event positioning in a monolithic annular PET scanner.

Autor:	Jaliparthi G; Center for Advanced Imaging, Department of Radiology, School of Medicine, West Virginia University, Morgantown, WV, United States of America., Martone PF; Center for Advanced Imaging, Department of Radiology, School of Medicine, West Virginia University, Morgantown, WV, United States of America., Stolin AV; Center for Advanced Imaging, Department of Radiology, School of Medicine, West Virginia University, Morgantown, WV, United States of America., Raylman RR; Center for Advanced Imaging, Department of Radiology, School of Medicine, West Virginia University, Morgantown, WV, United States of America.
Jazyk:	angličtina
Zdroj:	Physics in medicine and biology [Phys Med Biol] 2021 Jul 12; Vol. 66 (14). Date of Electronic Publication: 2021 Jul 12.
DOI:	10.1088/1361-6560/ac0d0c
Abstrakt:	PET scanners based on monolithic pieces of scintillator can potentially produce superior performance characteristics (high spatial resolution and detection sensitivity, for example) compared to conventional PET scanners. Consequently, we initiated development of a preclinical PET system based on a single 7.2 cm long annulus of LYSO, called AnnPET. While this system could facilitate creation of high-quality images, its unique geometry results in optics that can complicate estimation of event positioning in the detector. To address this challenge, we evaluated deep-residual convolutional neural networks (DR-CNN) to estimate the three-dimensional position of annihilation photon interactions. Monte Carlo simulations of the AnnPET scanner were used to replicate the physics, including optics, of the scanner. It was determined that a ten-layer-DR-CNN was most suited to application with AnnPET. The errors between known event positions, and those estimated by this network and those calculated with the commonly used center-of-mass algorithm (COM) were used to assess performance. The mean absolute errors (MAE) for the ten-layer-DR-CNN-based event positions were 0.54 mm, 0.42 mm and 0.45 mm along the x (axial)-, y (transaxial)- and z - (depth-of-interaction) axes, respectively. For COM estimates, the MAEs were 1.22 mm, 1.04 mm and 2.79 mm in the x -, y - and z -directions, respectively. Reconstruction of the network-estimated data with the 3D-FBP algorithm (5 mm source offset) yielded spatial resolutions (full-width-at-half-maximum (FWHM)) of 0.8 mm (radial), 0.7 mm (tangential) and 0.71 mm (axial). Reconstruction of the COM-derived data yielded spatial resolutions (FWHM) of 1.15 mm (radial), 0.96 mm (tangential) and 1.14 mm (axial). These findings demonstrated that use of a ten-layer-DR-CNN with a PET scanner based on a monolithic annulus of scintillator has the potential to produce excellent performance compared to standard analytical methods. (© 2021 Institute of Physics and Engineering in Medicine.)
Databáze:	MEDLINE
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