LIP - L ABORATORY OF I NSTRUMENTATION AND EXPERIMENTAL P ARTICLE PHYSICS Lisbon, PORTUGAL THE 12 TH VIENNA CONFERENCE ON INSTRUMENTATION FEV 2010 The ClearPEM Breast Imaging Scanner Jorge A. NEVES On behalf of the ClearPEM Collaboration PEM Collaboration
Motivation Breast Cancer and Positron Emission Tomography 2/ Breast cancer is the most common cancer among women mean incidence rate of 1.2 million females per year worldwide PET is a functional imaging technique that has demonstrated large potential for breast cancer detection - Positron Emission Mammography (PEM) Patient is injected with 18 F-FDG radiotracer that fix in tumor cells and decays by positron emission. The 2 γ photons resulting by the positron-electron annihilation are detected in temporal coincidence to imaging the biodistribution of the radiotracer. The ClearPEM Breast Imaging Scanner Jorge A. NEVES THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION FEV /18
The ClearPEM Scanner Detector Calibration Energy and Time Resolution Image Reconstruction Conclusions Outline The ClearPEM Scanner The ClearPEM Breast Imaging Scanner Jorge A. NEVES THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION FEV /18
Good spatial resolution ( ~ 1.5 mm in whole FoV) Fine crystal segmentation (2x2 mm) Dual APD readout of individual crystal pixels DoI measurements with good resolution (FWHM ~ 2 mm) High Sensitivity Long LYSO:Ce crystal (20 mm) Two detector plates with large active area (17x15cm 2 FOV) Reduced Random Background ( ~ 30%) Large flux of single photons (up to 10 MHz) Coincidence time resolution of ~ 4 ns FWHM The ClearPEM Scanner The ClearPEM Characteristics The ClearPEM Breast Imaging Scanner Jorge A. NEVES THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION FEV /18
ClearPEM MOVIE The ClearPEM Scanner The ClearPEM Breast Imaging Scanner Jorge A. NEVES THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION FEV /18
The ClearPEM Scanner The ClearPEM Detector Modules Two Detector Plates 160x180 mm 2 active area 6144 scintillation crystals LYSO:Ce (emit visible light when high energy photons interact with them) APD pixel channels ( Highly sensible photo- detector. Generate pulses in response to scintilation light) Double readout of crystal pixels for Depth-of- Interaction measurent (to minimize parallax effect) Water cooling system (18.0 ± 0.1 °C) Hamamatsu S8550 Avalanche Photo Diode LYSO:Ce 2x2x20 mm 3 crystal 4x8 crystal matrices made of BaSO 4 walls 384 APD arrays, Operating Voltage V ε ~ 511 keV 7.4 g.cm -3 The ClearPEM Breast Imaging Scanner Jorge A. NEVES THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION FEV /18
The ClearPEM Scanner FrontEnd ASIC ASIC or APD signal processing Charge Amplifier Characteristics Technology: AMS 0.35 μm CMOS, 70 mm 2 Area Input: 192 channels Output: 2 highest channels (192:2 mux) -> readout Compton events Max Input Charge: 90 fC Noise: ENC ~ 1300 e- ( Baseline RMS = 2.2 ADC counts = 5 keV) Shaping: 40 ns Analog Memories: 10 pulse samples Clock Frequency: MHz Power: 3.6 mW/channel The ClearPEM Breast Imaging Scanner Jorge A. NEVES THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION FEV /18
12 cm 4.5 cm ASICs (2x192 channels) FrontEnd Board Modules (12x32 crystals, 24 APDs) Super Module 2 FrontEnd Boards and 12 Detector Modules Processes 768 APD channels FrontEnd Board Contains 2 ASICs for signal selection 2 High-speed dual ADCs (10bits, 100MHz) 1 LVDS Channel Link Transmitter (600Mbps) Detector Head 8 Super Modules (16 for both DHs) 1 Service Board (HV & LV distribution, temperature monitoring) 2 water cooling plates The ClearPEM Scanner FrontEnd Electronics 192 Detector Modules (96 per DH) HV matrix Service Board The ClearPEM Breast Imaging Scanner Jorge A. NEVES THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION FEV /18
The ClearPEM Scanner Off-Detector and Data Acquisition Electronics DAE System – L1 Trigger/DAQ 4 DAQ Boards (Slave) 8 Xlinx TM FPGA First data filtering to identify usefull data (find Top- Bottom crystal coincidences) Check signal integrity calculating basic parameters Send relevant data to TGR/DCC Board 1 TGR/DCC – Trigger & Data Concentrator Board (Master) 1 Xilinx TM FPGA DAQ Board’s arbitration System’s Sync and Reset Responsible for the identification of coincidence between detector heads Sends relevant data to Acquisition Server (S-Link Bridge) Data Transfer Bandwidth 6.4 Gbps Trigger/DCC Acquisition Server 800 MBps S-Link FedKit (PCI) 60 MBps USB MBps Storage Rate Coincidence Triggering Rate 800 kHz 19’’ crate 2cPCI backplanes The ClearPEM Breast Imaging Scanner Jorge A. NEVES THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION FEV /18
The ClearPEM Scanner Scanner IPO Portuguese Institute of Oncology - Porto Examination Bed Detector Heads Robotic structure The ClearPEM Breast Imaging Scanner Jorge A. NEVES THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION FEV /18
511 keV APD pixel LYSO:Ce Crystal Relative Gain Distribution of Energy Calibrations Constants 3 Calibration constants per crystal (Top and Bottom readout) Detector Calibration Absolute Gain Distribution of pulse peak time Requires > 4%/mm for DOI resolution < 2 mm FWHM DOI Calibration The ClearPEM Breast Imaging Scanner Jorge A. NEVES THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION FEV /18
Tmax Tpeak Photon time is extracted from the pulse samples fitted by the function: Energy and Time Resolution Time Measurements Typical pulse 50 MHz sampling The coincidence time resolution of the whole scanner is 5.2 ns FWHM The ClearPEM Breast Imaging Scanner Jorge A. NEVES THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION FEV /18 Time Calibration
Energy and Time Resolution Energy Measurements Average energy resolution at 511 keV for the full scanner is 16.0 % 22 Na spectra for all crystals Photopeak measurements 511 keV photopeak compton Good energy linearity Energy resolution and photopeak position not dependent of DOI The ClearPEM Breast Imaging Scanner Jorge A. NEVES THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION FEV /18
Without DOI InformationWith DOI Information 1.2 mm FWHM Image Reconstruction ClearPEM Spatial Resolution Point Source Imaging 22 Na point source in a grid with 5 mm pitch Energy window keV Sinograms of 16 source positions are added 3D-OSEM/STIR Reconstruction Spatial Resolution Transaxial 1.2 mm FWHM (corrected by source size ~ 1 mm) DOI Effect Images without using DOI information show considerable blurring The ClearPEM Breast Imaging Scanner Jorge A. NEVES THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION FEV /18
Image Reconstruction ClearPEM Spatial Resolution Derenzo Phantom Imaging Sealed phantom with 22 Na gel 20 μ Ci activity (T 1/2 = 2.6y) Active area: 35 mm Ø x 38.1 mm length Phantom Draw 3.0 mm 2.5 mm 2.0 mm 1.5 mm 1.2 mm Dist. = 150 mm Takes = 4 x 20 min keV energy window 6 ns time window 3.0 mm 2.5 mm 2.0 mm 1.5 mm 1.2 mm D-OSEM The ClearPEM Breast Imaging Scanner Jorge A. NEVES THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION FEV /18
Image Reconstruction Initial Clinical Tests Example os a typical exam dose 7.6 mCi 150 mm detector plate opening 4 angular orientations coincidence windom ± 4 ns energy window keV low coincidences rate ~ 1.2 kHz fraction of randoms in FoV IS 35% Reconstruction 3D-OSEM simple normalization correction randoms, attenuation and scatter correction not applied 22 Na source data added to sinogram, emulating lesion (L/B ~ 4 for 3 mm lesion) The ClearPEM Breast Imaging Scanner Jorge A. NEVES THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION FEV /18
ClearPEM-Sonic Conclusions The ClearPEM Breast Imaging Scanner Jorge A. NEVES THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION FEV /18 ClearPEM electronics is one of the most innovative systems available for APD-based PET systems Excellent detector performance Time Resolution: 5.2 ns FWHM Energy Resolution: 16 % Spatial Resolution: 1.2 mm FWHM Initial clinical trials have been started Needs and efforts on image corrections
ClearPEM-Sonic The ClearPEM Breast Imaging Scanner Jorge A. NEVES THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION FEV /18 E. Albuquerque 1, F. G. Almeida 2,13, P. Almeida 3, E. Auffray 10, J. Barbosa 2, A. L. Bastos 9, V. Bexiga 1, R. Bugalho 4, C. Cardoso 4, S. Carmona 8, J.F. Carneiro 2, B. Carriço 4, C. S. Ferreira 4, N. C. Ferreira 5, M. Ferreira 4, M. Frade 4, F. Gonçalves 1, C. Guerreiro 5, P. Lecoq 10, C. Leong 1, P. Lousã 6, P. Machado 1, M. V. Martins 3, M. C. Martins 6, N. Matela 3, R. Moura 4, J.A.Neves 4, P. Neves 6, N. Oliveira 3, C. Ortigão 4, F. Piedade 6, J. F. Pinheiro 4, P. Relvas 6, A. Rivetti 10, P. Rodrigues 4, I. Rolo 4, M. Rolo 4, A. I. Santos 8, J. Santos 2, M. M. Silva 1, S. Tavernier 11, I. C. Teixeira 1,9, J. P. Teixeira 1,9, J. C. Silva 4,10, R. Silva 4, A. Trindade 4, J. Varela 4, 10 1 INESC-ID, 2 INEGI, 3 IBEB/FCUL, 4 LIP, 5 IBILI/FMUC, 6 INOV, 8 HGO, 9 IPO, 10 CERN, 11 VUB Funded by SFRH/BD/33667/2009 Acknowledgments Thank you!