基于半连续晶体的高分辨率深度测量PET探测器研究

小动物PET是一种高灵敏的分子影像仪器，广泛用于临床前生物医学研究。当前小动物PET通常采用双端读出晶体阵列、多层晶体阵列和连续晶体等具有深度测量能力的探测器来克服探测器的深度不确定效应，从而同时实现高空间分辨率和高效率。本项目提出了一种创新的长方体半连续晶体PET探测器，该探测器具有单端读出深度测量的能力，和双端读出晶体阵列的探测器相比，晶体阵列制作和光探测器成本大幅度降低；和连续晶体探测器相比，边缘效应对探测器位置分辨率的影响大幅度降低。本项目将在我们前期研究取得良好结果的基础上，进一步优化晶体探测器参数和研究三维定位算法，研发适用于该探测器的SiPM阵列读出电路和可在线计算三维位置的信号处理电路。最终目标是研发长度满足小鼠单床位全身成像的高三维位置分辨率半连续晶体PET探测器及其所需电子学电路，为今后使用该探测器研发全视野均匀亚毫米分辨率、高灵敏和低成本的小动物PET系统奠定基础。

Small animal positron emission tomography (PET) scanner is a high sensitivity molecular imaging instrument which is widely used in preclinical biomedical research. Usually depth encoding detectors such as dual-ended readout scintillator arrays, multi-layer scintillator arrays and monolithic scintillators were used to overcome the depth of interaction uncertainty effect and simultaneously achieve high spatial resolution and high sensitivity for small animal PET scanners. In his project a novel PET detector based on cuboid semi-monolithic scintillator that can measure the depth of interaction with single-ended readout is proposed. The proposed detector significantly reduces the costs of both scintillator array manufacture and photodetectors as compared with the dual-ended readout scintillator detector, and significantly reduces the edge effect that degrades the spatial resolution of the detector as compared with the monolithic scintillator detector. Based on the good preliminary results achieved on this detector, in the work the parameters of scintillator will be further optimized and three-dimensional positioning algorithm will be studied. The SiPM array readout circuits and signal processing electronics that can perform three-dimensional position estimation on-line will be developed for the detector. The final aim of this project is to develop a PET detector based on cuboid semi-monolithic scintillator that is long enough for mouse whole body imaging in a single bed position and achieves high position resolution in three dimensions and the required electronics of the detector. The outcome of this project will lay a strong foundation to develop a small animal PET scanner with sub-millimeter uniform spatial resolution, high sensitivity and low cost in the future.