适用于放射自显影的GAGG/SiPM探测器的空间分辨率物理极限研究

放射自显影（简称AR）是一种测量由放射性核素标记的药物在生物体内分布的生物组织切片成像技术，具有高清晰度和高定量精度的优点，是活体核素成像研究的金标准。近年来SiPM光探测器技术的不断成熟为研发基于SiPM的高分辨率和高效率AR探测器创造了条件。在我们前期基于SiPM研发高分辨率PET探测器的基础上，本项目计划采用1 mm厚的高密度和高光输出的GAGG连续晶体薄片和晶体单元为0.1-0.3 mm的分割晶体阵列，以及单元大小为1 mm的高分辨率SiPM阵列，结合创新的电子学、数据采集和图像显示软件的开发，探索基于闪烁晶体耦合光电转换器类型探测器可以达到分辨率的物理极限，研发分辨率达到0.1-0.3 mm的AR探测器。本项目研发的AR探测器具有高灵敏度，可以进行能量测量、光子计数、实时显示、脉冲形状甄别（α和β），不需要制冷、简单和成本低等优点，适合于α，β和低能γ成像。

Autoradiography (AR) is specimen imaging technology that measuring the biodistribution of radiolabeled molecules inside the body of living objects. It has advantage of high spatial resolution and high quantitative accuracy and is the gold standard of in vivo nuclear imaging. In recent years, the development of SiPM technology enables the possibility of developing SiPM based high resolution and high efficient AR detector. Based on our previous successful work on developing high resolution PET detectors by using SiPM, in this proposal we propose to use high density and high light output GAGG scintillator of both monolithic slab and segmented array with crystal size of 0.1 to 0.3 mm, with 1 mm thickness for both, and high resolution SiPM array with a pixel size of 1 mm to develop AR detectors with spatial resolution of 0.1 to 0.3 mm. Novel electronics, data acquisition and image display software will be developed. The physical limit of the spatial resolution of detector using scintillator and photodetector combination will be explored. The AR detector developed in this work is sensitive and capable of measuring energy, photon counting, displaying image in real time, discriminating α and β particles by using pulse shape. The detector is simple, low cost, no cooling required and can be used for α, β and low energy γ ray imaging.