Abstract

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Author(s):: LI Minghui1; CHEN Yilun2; 3; RAN Hu2; 3; 4; DAI Jianrong1; MEN Kuo1; ZHAO Chengxin2; 3; NIU Chuanmeng1; WANG Hongkai1; 1. Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China 2. Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China 3. School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing 100049, China 4. School of Mathematics and Physics, Chengdu University of Technology, Chengdu 620035, China

Keywords:: Keywords: proton radiography Monte Carlo pixel detector scattering suppression

Abstract:: Using high-energy proton to image the region of interest can directly obtain the accurate estimation of the proton stopping power of the lesions, which is of great significance to reduce the range uncertainty in proton therapy. As a fundamental function of proton computed tomography (CT), radiographic imaging plays a crucial role in assisting clinical positioning. The study develops a compact proton CT detector based on an active array pixel CMOS chip in Monte-Carlo simulation toolkit Geant4, and evaluates the radiographic imaging capability of the system using 180 MeV protons. The angles of tracks are successfully reconstructed. CTP404, CTP528, and the CTP515 of specific materials are used for simulation, obtaining the spatial and density resolutions, and measuring the proton relative stopping power (RSP). The image signal-to-noise ratio is improved when using 2° proton scattering angle cut-off value. The spatial resolution is 3-4 lp/cm measured using CTP528 module. The density resolution is better than 0.05 g/cm3, and the RSP resolution is within 5% when CTP404 module is used. Through the imaging of CTP515 phantom of specific material, it is demonstrated that the system has potential for imaging common human tissues.