Simulation study of a 50 ps panel TOF PET imager

Abstract

Positron emission tomography (PET) is one of the most important diagnostic tools in medicine, providing three-dimensional imaging of functional processes in the body. The method is based on detecting two gamma rays originating from the point of annihilation of the positron emitted by a radio-labeled agent and used to follow the human’s physiological processes. In Time-Of-Flight PET, gamma rays’ arrival time is measured in addition to their position. The coincidence timing resolution (CTR) of state-of-the-art scanners is between 200 ps and 500 ps FWHM, which can significantly improve the contrast in imaging large objects. However, increasing the sensitivity of the next-generation PET scanners requires increasing the imaging device’s timing accuracy. Using the latest advances, a multichannel system with improved CTR is becoming technologically possible. Generally, 3D images from limited angle PET scanners are distorted and have artifacts. Fortunately, with improving timing resolution of PET gamma detectors, artifact-free images can be obtained even by a very simplified detector. We were studying a simple panel PET detector consisting of gamma detectors with 50 ps coincidence timing resolution. With this new concept, the price of PET scanners for imaging single or multiple organs can be drastically decreased. We evaluated different panel detector arrangements by imaging different phantoms. The reconstructed images were compared with those obtained with the Siemens Biograph Vision, a state-of-the-art clinical PET scanner. We found comparable image quality parameters of both systems when the CTR approaches 50 ps FWHM and that good CTR can partially compensate for smaller gamma detection efficiency.