Mechanical Design And Detector Research For Brain-dedicated PET

Positron emission tomography（PET）system uses radionuclides that can participate in physiological metabolism to obtain two-dimensional or three-dimensional metabolic images of patients’tissues or organs.It is significant for the early diagnosis and efficacy evaluation of tumors,heart and brain diseases,organ function research and drug development etc.The brain-dedicated PET system is aimed at the human brain.It has a smaller size and higher resolution and sensitivity compared with the whole-body PET system.It can accurately image brain metabolism,which is helpful for the diagnosis of brain diseases and brain science research.The paper focuses on the research demands of the brain-dedicated PET system and the following four aspects of the research are carried out:1)Polyhedral brain-dedicated PET mechanical structure design and analysis;2)Portable brain-dedicated PET mechanical structure design;3)Research on optical simulation and decoding of front-endγphoton detector of PET system;4)Electronic collimation experiment of polygon slice crystal detector.First of all,a set of polyhedral brain-dedicated PET system with opening and closing movement based on truncated icosahedron was designed with the effect of the geometric structure of the PET system on performance studied,and the detector and other modules were designed and calculated in detail.The strength and deformation of key parts in the body were analyzed and checked with the finite element method,which further improved the stability of the system.Secondly,for the needs of flexible testing,based on the existing PET technology,a portable brain-dedicated PET device based on a ring structure was designed.The device is lightweight and convenient,with higher sensitivity and resolution compared to traditional PET systems,which could be a parallel scheme for brain-dedicated PET systems.Then,guided by the accurate decoding of the PET system detector,optical simulation of detectors was carried out with Trace Pro software.Three geometric analysis methods and a neural network decoding method were proposed for decoding lamellar crystal detectors.The neural network method got excellent performance.The decoding spatial resolutions are about 0.452 mm and 0.859 mm respectively in the edge area and the center area,which effectively realizes the accurate decoding of the polygon detector.Finally,for the needs of assembling high-performance detectors,an electronic collimation experiment device of a regular hexagonal detector was built,and a ²²Na point source was used to perform the collimation experiment.The light distributions with obvious characteristics were obtained,but the decoding effect is not satisfactory,and further research is needed.This paper has conducted preliminary research on the mechanical structure and detectors of brain-dedicated PET system,which can provide reference information for the development of brain-dedicated PET system.