Application of High Energy Physics Technologies to PET (Positron Emission Tomography) Chin Tu Chen, Ph.D. Committee on Medical Physics & Department of Radiology Pritzker School of Medicine & Biological Sciences Division The University of Chicago National Science Foundation Visit, June 26, 2007
HEP & PET Similarities and differences PET Scanner Calorimeter HEP Biomedical Imaging CM S Differences Energy range (10GeV 511keV) No synchronisation > free running electronics Multiple vertices 200 P. Le Du/Saclay 28,700 ph/mev ER = 10.1% Counts Similarities Geometry and granularity Detector (Crystals & scintillator) Sensor (PM,APD) Electronics:Fast (40 MHz), compact Event rate & Data volume (Gbit/s) 400 600 Energy (kev) 800 1000
From HEP to Medical Imaging Where techniques are transferred to developments in biomedical field Medical Imaging has so far only partially benefited from new technologies developed for High Energy Physics detectors New scintillating crystals and detection materials CMS (WPbO4) Luap (Crystal Clear col) Photodetectors : Highly segmented and compact PMT APD SiPM APD : SSC/SDC (1991) CMS (1996) MicroTEP TEP Electronics & signal treatemnt Highly integrated Fast, low noise,low power preamp Digital filtering and signal analysis Trigger/DAQ High level of parallelism and event filtering algorithms Pipeline and parallel read out, trigger and on line treatment Simulation & Computing Modern and modular simulation software using worldwide recognized standards (GEANT) P Le Du/Saclay
PET: Molecular Imaging of Life and Life Processes P a t ie n t 1 Live Brain MR PET P a t ie n t 2 Dead Brain MR PET
PET Principle P N + e+ + n + energy E = mc2
Production of Isotopes (Mini Cyclotron) O (p,n) 18F 18
PET Isotopes 15 O 13 N C 11 18 F PET Tracers [15O] O2 [15O] H2O Cu 64 82 Rb I 124 [15O] H2O [15O] CO [13N] NH3 [18F] FDOPA [13N] glutamate [18F ] [11C] acetate [18F] FDG [11C] palmitate
18 Fluoro 2 deoxy D glucose PLASM A T IS S U E O H FDG FDG FD G 6 P O O H HO g lu c o s e g lu c o s e g lu c o s e 6 O H F 18 [1 8F ] F D G C O2 + H O 2
LU N G S Normal PM RV Alzheimer s Disease L IV E R APPR O JEC TIO N LV
Biochemical Imaging with Small Animals 11 CH3 N O OCH3 F [11C]WIN 35,428 0.2 cps 0.15 striatum cerebellum 0.1 0.05 micropet 0 0 10 20 30 Time(min) 40 50
Human PET: 3 4mm; Target: 1mm Animal PET: 1 2 mm; Target: <0.5mm Fast Dynamic Image Acquisition High Resolution & High Sensitivity High Performance & Low Cost (HPLC)
Multi Modality Image Integration Fusion of PET & MRI
PET/CT Imaging
Multi Modality Integrative System PET/SPECT PET/MRI PET/SPECT/CT For Animal Imaging Siemens Molecular Imaging
Multi Modality Bayesian Image Reconstruction Upper Two: 1. Co registration of PET/SPECT with CT/MRI Filtered BackProj. 2. Incorporation of high resolution information from the co Lower Two: registered CT/MR images into a Bayesian image recons truction framework to enhance image quality of PET/SPECT Multi Modality 5. Using the co registered CT/MR images as an anatomic map Image Reconstru. in correction for attenuation and scatters in PET or SPECT Chen, Kao, et al
A Benchtop Prototype for High Throughput Animal Imaging HRRT modules LSO crystals with DOI capability good spatial resolution ~2.42mm crystal pitch ~10mm DOI resolution good detection sensitivity high count rate large detection sensitive area ~25.2cm 17.4cm 72 104 crystals per layer off shelf, well tested, cost effective design adjustable energy and coincidence windows
Flexible Configuration Fully 3D Reconstruction without Angular Rotation \
Stationary Compact Dual Panel PET with Very High Sensitivity
High-Throughput Compact PET RFOV = 56.3mm True Compact, Convent l Compact, no PSF scanner with PSF FOV 57.3mm Compact FOV 85.9mm Conventional
DOI Detectors Phoswich detectors GSO/LSO LSO PMT photo diodes (or SiPM/MPPC) scintillator (BGO) photo diode/sipm PMT
Time-of-Flight Tomograph x D Can localize source along line of flight - depends on timing resolution of detectors Time of flight information can improve signal-to-noise in images - weighted backprojection along line-ofresponse (LOR) x = uncertainty in position along LOR = c. t/2 Karp, et al, UPenn
300 ps TOF Benefit of TOF Better image quality Faster scan time 5Mcts TOF 1Mcts TOF 5Mcts 1Mcts 10 Mcts 5 Mcts 1 Mcts no TOF Karp, et al, UPenn
TOFPET DREAM PET without TOF (>99%) One Commercial TOFPET System Available with 750 picosec TOF (11.25 cm LOR Resolution) 30 picosec TOF 4.5 mm LOR Resolution 10 picosec TOF 1.5 mm LOR Resolution 3 picosec TOF 0.45 mm LOR Resolution Histogramming No Image Reconstruction
Pipeline Architectures LHC Future PET Digitisation Pipeline Event builder P. Le Du/Saclay
Proposal of Front End Architecture A 2 3 4 5 clock 50 MHz photo detector crystal PMT APD SiPM B C 1 6 Other ROI channels 7 Trigger logic 8 digital filter charge preamplifier shaper CR RC A D C 7 bits Pipelined register LOCAL BUFFER ROI Data E,T,Q Pixelised Trigger logic processes raw fast information Free running sampling ADC Digital filter used to extract pulse amplitude and high resolution timing Pipelined processing architecture to avoid deadtimes Only one channel to compute either the energy and time Data Acquisition P. Le Du/Saclay
Geant4 A Common Simulation Platform High High Energy Energy Physics Physics Space Space and and Radiation Radiation Higgs event at LHC (CMS) with Geant4 Medical Medical Technology Technology Transfer Transfer GATE Geant4 Application for Tomographic Emission
SiPM/PET Collaboration at ANL/UC