The Design Of Data Acquisition And Processing System For PET Based On ZYNQ

Positron emission tomography(PET)technology has developed rapidly in recent years and has a wide range of applications in medical diagnosis.PET data collection and coincidence processing technology is one of the key technologies of PET.Since the amount of coincidence data of 3D scanning imaging is much higher than that of2 D scanning imaging.Therefore,a set of PET acquisitions with high transmission rate,high versatility and high stability have been developed The system will greatly promote the overall performance of the PET system.In recent years,with the development of embedded systems,programmable system-on-chips can make the entire system on one chip,and use the method of software and hardware collaboration to make the hardware design on FPGA and the software design on ARM interactive,So that embedded development is more efficient.In this paper,Xilinx's Zynq-7000 series fully programmable system-on-chip is used,and the new architecture of ARM + FPGA is used as the design platform to study and implement the PET data acquisition system.At the same time,the conforming data transmitted from the PET acquisition system to the host computer is processed.In this article,the main work studied is as follows:(1)PET data acquisition system based on ZYNQ was built.The system uses the programmable features of ZYNQ development software and hardware and rich IP cores to realize functions such as data caching,board communication and machine tool control.The entire system uses the Zynq-7020 chip as the control core,and uses the SDK for software development,setting DMA data transmission,clock timing,GPIO control of the board,serial port and machine tool communication,etc.Building PET data acquisition system on this platform not only improves the speed of the PET data acquisition,but also makes the entire PET system more compact and cheaper.(2)The interface of PET acquisition was built.The interface is designed on the VS2010 platform and is used to control and debug the hardware circuit of the PET data acquisition system.It mainly realizes the response to user operation commands,by the optical fiber transmits the commands to the hardware control circuitof the acquisition system,and then collects the batch data generated by the hardware circuit and processes the data.It mainly includes the functions of realizing communication between hardware and software,hardware system parameter configuration and work control,receiving data from the acquisition system,processing the data and making corresponding graphic display.(3)Testing and Correction of The Coincidence Channel Time deviation in PET.By measuring the clock signal of the coincidence channel of the clock communication control panel,According to the measured time deviation value,time correction can be achieved by adjusting the length of the clock line to reduce the time deviation of the coincidence channel.The results show that by utilizing this method,one can obtain ideal coincidence time spectrum,and detect the deviation of PET coincidence detection system rapidly and effectively at the same time.(4)Coincident Time Spectrum Characteristics of PET System.This method is applied to PET test system by adjusting the length of each clock line to achieved the coincidence channel time correction.Two sets of coincidence data were obtained on this system with11.1×107Bq 18F-fluorodeoxyglucose(FDG)and 68 Ge rod source emissions respectively.The time difference of coincidence events the statistical generates time spectra of the two detector units within the coincidence range,a real time spectrum and an ideal time spectrum of a PET system,and a normalized time spectrum of a PET system.By counting coincidence data obtain time spectrum,one can clearly observe the normal and abnormal time spectrum,and quickly understand the time difference of PET coincidence channel and the statistical distribution of the coincidence events.