基于像素化芯片的质子透射成像模拟研究  

Simulation study of proton radiography based on pixel sensors

作　　者：李明辉 陈轶伦 冉虎 戴建荣 门阔 赵承心 牛传猛 王宏凯 LI Minghui;CHEN Yilun;RAN Hu;DAI Jianrong;MEN Kuo;ZHAO Chengxin;NIU Chuanmeng;WANG Hongkai(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;Institute of Modern Physics,Chinese Academy of Sciences,Lanzhou 730000,China;School of Nuclear Science and Technology,University of Chinese Academy of Sciences,Beijing 100049,China;School of Mathematics and Physics,Chengdu University of Technology,Chengdu 620035,China)

机构地区：[1]国家癌症中心/国家肿瘤临床医学研究中心/中国医学科学院北京协和医学院肿瘤医院放疗科,北京100021 [2]中国科学院近代物理研究所,甘肃兰州730000 [3]中国科学院大学核科学与技术学院,北京100049 [4]成都理工大学数理学院,四川成都620035

出　　处：《中国医学物理学杂志》2024年第9期1064-1069,共6页Chinese Journal of Medical Physics

基　　金：国家自然科学基金青年基金(12205374);北京市自然科学基金(1232033)。

摘　　要：利用高能质子对病灶区域进行成像,直接获得病灶区域对质子的阻止能力,对于减小质子治疗中射程不确定度具有重要意义。作为质子CT的基本功能,透射成像对于辅助摆位具有重要意义。本研究在Geant4程序中设计并构建基于有源阵像素CMOS芯片的紧凑型质子CT探测器,并利用180 MeV质子对该系统的透射成像能力进行评估。通过径迹角度进行精确重建,对CTP404、CTP528以及自定义材料的CTP515模块进行模拟,获得空间、密度分辨力,以及质子相对阻止能力RSP的模拟结果。结果显示选用2°质子偏转角截断值时图像信噪比得到提升,使用CTP528模块测算的空间分辨力为3~4 lp/cm;使用CTP404模块测算密度分辨力优于0.05 g/cm^(3),RSP分辨力在5%以内;通过对选定材料的CTP515模块进行成像,表明该系统具备用于人体常见组织成像的潜力。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/cm^(3),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.

关 键 词：质子透射成像 蒙特卡罗 像素探测器 散射校正 

分 类 号：R318[医药卫生—生物医学工程] R811.1[医药卫生—基础医学]