Research And Implementation Of Small Animal PET Detector And Data Transmission System

In the biomedical field,research on human diseases usually needs to be performed on animal models to understand the molecular biological characteristics of the disease.In recent years,Positron Emission Tomography(PET)imaging technology has been introduced into small animal science research experiments and can be widely used in the early stages of various diseases(tumor,cardiovascular disease,and neurological disease,etc.)Diagnosis,treatment planning and efficacy evaluation,as well as biomedical research and new drug development.PET uses positron nuclide-labeled tracer molecules for live imaging.It can dynamically and quantitatively observe the physiological changes of living organisms at the molecular level,and has outstanding research significance and role in promoting the progress of the entire biomedical field.The small animal PET system includes a detector module,a Front-End Electronics(FEE)module,a Single Processing Unit(SPU),and a Coincidence Processing Unit(CPU).PET detectors usually consist of scintillation crystal arrays and photodetectors.They are used to detect gamma photons to track positron-labeled bioprobes.They are one of the most important components of PET systems.Traditional non-DOI detector cannot measure depth of information,therefore can not achieve high spatial resolution and high sensitivity at the same time.In order to make up for the inadequacies of traditional detector,this subject is to start with the structure design of the detector,from the choice of scintillation crystals and photoelectric converters,the optimization and selection of the thickness of the light guide,The material selection between the crystal-reflective layers was comprehensively considered,and a dual-ended readout design scheme was adopted.By testing several important performance indicators of the detector,a new type of silicon photomultipliers(Si PM)arrays coupled to lutetium-yttrium oxyorthosilicate(LYSO)arrays was developed.The dual-ended readout depth of the LYSO array was measured with a PET detector to achieve full-field high resolution and high sensitivity at the same time,thereby meeting the needs of small animal PET imaging systems.The data transmission between the SPU and the CPU in the PET system is also one of the important components,and it is a hub connecting various modules of the system.The entire system contains 12 SPU modules and one CPU module.The data volume of each SPU is about 120 Mbps.The CPU needs to process the data of 12 SPUs.The structure is complicated and the system requires high reliability for data transmission and high real-time performance.Considering the limited storage space of the system,several commonly used data transmission schemes were compared and analyzed.Finally,an effective data transmission system was built using Gigabit Ethernet.The test results showed that the transmission scheme based on Gigabit network can guarantee the bandwidth of data transmission.Stable and ensure the real-time transmission.This project focuses on the small animal PET imaging system,and aims to realize a full-field,high-resolution,high-sensitivity system.Starting from the two aspects of detectors and data transmission schemes,the dual-ended readout depth coding detection based on Si PM and LYSO arrays is designed.The device and the Gigabit Ethernet-based data transmission scheme lay a solid foundation for the future development of a high-efficiency,full-field uniform high spatial resolution and low-cost small animal PET imaging system using the detector and the transmission system.