1、2015新一代辐射探测技术与公众安全高峰论坛报告2015年7月11日先进PET电子学系统的开发和研制PET SYSTEM INTRODUCTIONDetectorScintillatorPhoton sensorData acquisition electronicsDetector readoutCoincidence Imaging process and reconstructionADVANCED PET TECHNOLOGYPET imaging system performance Goal:High ResolutionHigh SensitivityDetector techn
2、ology:Silicon based photon sensor(SiPM)Depth of Interaction(DOI)measurementData acquisition electronicsTime-of-flight measurementHigh counting rate and high channel number support System design:Multi-modality system support:PET/MR,PET/CT,PET/MR/CTSIPM PHOTON SENSORMR compatible!DOI MEASUREMENT DOI m
3、easurement in detector:reduce parallel error for LOREspecially useful for small system or compact system desginWith DOI Without DOI DOI MEASUREABLE DETECTOR DESIGNTIME OF FIGHT MEASUREMENT Time of Fight measurement can improve PET imaging performance Sub-nano second timing resolution is needed for p
4、ractical ToF application LARGE SIZE SIPM BASED DETECTOR DESIGNCrystal pixel size:2 x 2 x 30 mm3Overall detector size:65 x 65 x 40 mm3Crystal number:32 x 32=1024SiPM:Hamamatsu MPPC array 5 x 5 x 2=50Total SiPM readout channels:20 x 20 x 2=800CHALLENGING FOR FRONT-END READOUTHigh resolution more pixel
5、 readoutDOI readout readout channel number doublesHigh sensitivity high counting rateCompact size low power consumption and small form factor Summary of design target:High readout channel number with high counting rate capability in small sizeImpossible?Channel reduction technology:signal multiplexi
6、ngSpecial ASIC readout chip design SIGNAL MULTIPLEXINGChange individual readout into X and Y readout Reduce SiPM readout channels:from 800 to 80 RbRbRbMPPCMPPCMPPCRbRbRbMPPCMPPCMPPCRbRbRbRbRbMPPCRbMPPCMPPCRbRbRbRbY1Y2X1YnX2RbXnRbRgRgRg.RgRgRgRgRgRgSIPM READOUT ASICDevelopment codeTIMPIC IIInput chan
7、nel number16Power consumption10mW/chInput signal range10pC 1000pCIntrinsic timing resolution20-30ps FWHMCMOS technology0.35umPackageBGA 121 pinsFRONT-END READOUT ELECTRONICSNO ADCs neededFPGA directly process the output of ASICAll analog signal converted in front-endOutput to LVDS cable 64 channels
8、for each front-end readout boardCounting rate:up to 1M/s200400600800100012001400020040060080010001200Linearity test resulty=308.88+1.0835x R=0.99909 TQ output(ns)input pulse(pC)COMPARE WITH TRADITIONAL PET DATA ACQUISITION SYSTEMTraditional CFD,ADCand TDC basedPure digital ASIC and FPGA basedDETECTO
9、R MODULE PERFORMANCE DETECTOR MODULE PERFORMANCE 17%18%28%DOI resolution is about 4mmDATA ACQUISITION ELECTRONICS DESIGNLVDS data transfer rate:1.0 Gb/sOverall front-end data transfer rate:up to 48Gb/sMaximum input channel number:3072Maximum front-end counting rate 48M/sMaximum coincidence event rat
10、e:12.5M/sSystem timing resolution:0.3ns bin size with 0.6ns FWHM(ToF)DATA ACQUISITION ELECTRONICS SYSTEMPROTOTYPE PET SYSTEM 1Rotating PET systemFOV size about 57 mmFor small animal PET imagingSystem built in 2012PROTOTYPE PET SYSTEM 2Square shape PET systemFOV size about 79 mmFor small animal PET i
11、magingSystem built in 2014 IMAGING RESULTS PHANTOMSystem resolution:1.5mmDOI is very important in high resolution compact systemWith DOI Without DOI IMAGING RESULTS-MOUSEBRAIN/BREAST PET SYSTEM Square shape PET systemFOV size about 320 mmFor Brain/Breast PET imagingSystem is projected to be built in
12、 2015 PROTON THERAPY APPLICATIONPET system is used to do proton beam range verification in proton therapySUMMARYPET development trends:SiPM photon sensorDOI measureable ToF measureableMulti-modality Imaging system(PET/CT,PET/MR)supportAdvanced electronics design for PET data acquisition large scale signal multiplexing Special ASIC chip designPure digital DaQ system Ongoing:Brain/Breast PETFuture:Whole body PET,PET/MR systemTHANKS
