LIP - LABORATORY OF INSTRUMENTATION AND EXPERIMENTAL PARTICLE PHYSICSLisbon, PORTUGAL
THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION
15-20 FEV 2010
The ClearPEM Breast Imaging Scanner
Jorge A. NEVESOn behalf of the ClearPEM Collaboration
PEMCollaboration
Motivation
Breast Cancer and Positron Emission Tomography
01
10
11 np2/ ν
γ 511keVγ 511keV e+ e-
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 18F-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 15-20 FEV 20102/18
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 15-20 FEV 20103/18
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 (17x15cm2 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 15-20 FEV 20104/18
ClearPEM MOVIE
The ClearPEM Scanner
The ClearPEM Breast Imaging Scanner Jorge A. NEVES
THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION 15-20 FEV 20105/18
The ClearPEM Scanner
The ClearPEM Detector ModulesTwo Detector Plates
160x180 mm2 active area
6144 scintillation crystals LYSO:Ce (emit visible light when high energy photons interact with them)
12288 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 mm3 crystal
4x8 crystal matrices made of BaSO4 walls
384 APD arrays, Operating Voltage 350-450V
ε ~ 82% @ 511 keV
7.4 g.cm-3
The ClearPEM Breast Imaging Scanner Jorge A. NEVES
THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION 15-20 FEV 20106/18
The ClearPEM Scanner
FrontEnd ASIC
ASIC or APD signal processing
Charge Amplifier Characteristics Technology: AMS 0.35 μm CMOS, 70 mm2 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: 50-100 MHz
Power: 3.6 mW/channel
The ClearPEM Breast Imaging Scanner Jorge A. NEVES
THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION 15-20 FEV 20107/18
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)
192 Detector Modules (96 per DH)
HV matrix
Service Board
The ClearPEM Breast Imaging Scanner Jorge A. NEVES
THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION 15-20 FEV 20108/18
The ClearPEM Scanner
Off-Detector and Data Acquisition Electronics
DAE System – L1 Trigger/DAQ4 DAQ Boards (Slave)
8 XlinxTM 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 XilinxTM 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 (520) @ S-Link FedKit (PCI)
60 MBps (42) @ USB 2.0
400 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 15-20 FEV 20109/18
The ClearPEM Scanner
Scanner Integration @ IPO
Portuguese Institute of Oncology - Porto
Examination BedDetector Heads
Robotic structure
The ClearPEM Breast Imaging Scanner Jorge A. NEVES
THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION 15-20 FEV 201010/18
511 keV
APD pixel
APD pixel
LYSO:Ce Crystal
Relative Gain
Distributio
n of Energ
y Calib
rations C
onstants
3 Calibration constants per crystal (Top and Bottom readout)
Detector Calibration
Absolute Gain
Distribution of pulse peak timeRequires > 4%/mm for DOI resolution < 2 mm FWHM
DOI Calibration
The ClearPEM Breast Imaging Scanner Jorge A. NEVES
THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION 15-20 FEV 201011/18
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 15-20 FEV 201012/18
Time C
alibratio
n
Energy and Time Resolution
Energy MeasurementsAverage energy resolution at 511 keV for the
full scanner is 16.0 %
22Na spectra for all crystals
Photopeak measurements
511 keV photopeakcompton
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 15-20 FEV 201013/18
Without DOI Information
With DOI Information
1.2 mm FWHM
Image Reconstruction
ClearPEM Spatial ResolutionPoint Source Imaging
22Na point source in a grid with 5 mm pitch
Energy window 400-600 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 15-20 FEV 201014/18
Image Reconstruction
ClearPEM Spatial ResolutionDerenzo Phantom Imaging
Sealed phantom with 22Na gel
20 μCi activity (T1/2 = 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 mmTakes = 4 x 20 min
450-600 keV energy window6 ns time window
3.0 mm
2.5 mm
2.0 mm
1.5 mm
1.2 mm
3996 0
3D-OSEM
The ClearPEM Breast Imaging Scanner Jorge A. NEVES
THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION 15-20 FEV 201015/18
Image Reconstruction
Initial Clinical TestsExample os a typical exam
dose 7.6 mCi 150 mm detector plate opening 4 angular orientations coincidence windom ± 4 ns energy window 400 - 650 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 22Na 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 15-20 FEV 201016/18
ClearPEM-Sonic
Conclusions
The ClearPEM Breast Imaging Scanner Jorge A. NEVES
THE 12TH VIENNA CONFERENCE ON INSTRUMENTATION 15-20 FEV 201017/18
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 15-20 FEV 201018/18
E. Albuquerque1, F. G. Almeida2,13, P. Almeida3, E. Auffray10, J. Barbosa2, A. L. Bastos9, V. Bexiga1, R. Bugalho4, C. Cardoso4, S. Carmona8, J.F. Carneiro2, B. Carriço4, C. S. Ferreira4, N. C. Ferreira5, M. Ferreira4, M. Frade4, F. Gonçalves1, C. Guerreiro5, P. Lecoq10, C. Leong1, P. Lousã6, P. Machado1, M. V. Martins3, M. C. Martins6, N. Matela3, R. Moura4, J.A.Neves4, P. Neves6, N. Oliveira3, C. Ortigão4, F. Piedade6, J. F. Pinheiro4, P. Relvas6, A. Rivetti10 , P. Rodrigues4, I. Rolo4, M. Rolo4, A. I. Santos8, J. Santos2, M. M. Silva1, S. Tavernier11, I. C. Teixeira1,9, J. P. Teixeira1,9, J. C. Silva4,10, R. Silva4, A. Trindade4, J. Varela4, 10
1 INESC-ID, 2 INEGI, 3 IBEB/FCUL, 4 LIP, 5 IBILI/FMUC, 6 INOV, 8 HGO, 9 IPO, 10CERN, 11VUB
Funded bySFRH/BD/33667/2009
Acknowledgments
Thank you!