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Small Animal Fast Insert for mRi
Chiara Casella
IPP, ETH Zurich
DPNC, Université de Genève
May, 6th - 2015
Small Animal Fast Insert for mRi
magnetic
Resonance
imaging
scanner
- mice
- rats
Chiara Casella
06.05.2015
Small Animal Fast Insert for mRi
a PET detector
(Positron Emission Tomography)
i.e. medical imaging
Chiara Casella
06.05.2015
OUTLINE
• introduction
• the
•
•
•
: PET, PET/MRI, state of the art
SAFIR detector
what’s special in SAFIR ?
how this will be achieved ?
why in the context of HEP ?
• status
of the project
• results (preliminary!)
•
•
•
simulations
reconstruction
hardware activities
Chiara Casella
-2-
06.05.2015
Positron Emission Tomography (PET)
nuclear medicine imaging technique for in-vivo functional analysis with excellent
sensitivity at molecular level
p → n + e+ + νe
e+ e− → γγ
(Eγ = 511 keV )
[3]
[1]
[2]
[3]
1. positron emission
2. positron/electron annihilation
3. two gamma photons (colinear, 511 keV)
A.Del Guerra, CERN Academic Training 2009
result : image of functional processes in the body
Chiara Casella
-3-
06.05.2015
Positron Emission Tomography (PET)
Early PET images
D. Townsend, A. Jeavons
CERN, 1977
first reconstructed image of
the skeleton of a mouse
injected with 18-F
detector : HIDAC ~ wire
chamber (from G. Charpak)
“You are indeed correct that the birth
of PET is somehow controversial”
(D. Towsend)
Chiara Casella
-4-
06.05.2015
Positron Emission Tomography (PET)
microPET
myocardial perfusion (Rb-82) in a normal patient
FDG-PET for Metastatic Melanoma
stress
Chiara Casella
rest
F-18 young rat imaged with the
AX-PET Demonstrator
-5-
huge domain of applications
both in clinical and pre-clinical fields
- full body / brain /or organs-specific
- oncology (diagnosis, tumor staging)
- study of neurogerenerative diseases
- psychology
- cardiac functioning monitoring
- in-beam monitoring in hadron-therapy
- medical research
- pharmacokinetics
- development of new tracers
06.05.2015
Positron Emission Tomography (PET)
microPET
myocardial perfusion (Rb-82) in a normal patient
FDG-PET for Metastatic Melanoma
stress
Chiara Casella
rest
F-18 young rat imaged with the
AX-PET Demonstrator
-5-
huge domain of applications
both in clinical and pre-clinical fields
- full body / brain /or organs-specific
- oncology (diagnosis, tumor staging)
- study of neurogerenerative diseases
- psychology
- cardiac functioning monitoring
- in-beam monitoring in hadron-therapy
- medical research
- pharmacokinetics
- development of new tracers
06.05.2015
Magnetic Resonance Imaging (MRI)
- physics basis : Nuclear Magnetic Resonance (NMR)
- H : most abundant element in the body
=> primary focus of MRI: H spins
ΔΕ = μΒ0
[~ 100 MHz]
i.e RF domain
gradient coil
- vary linearly Bo differently in x,y,z
- responsible of the localization of
the MR signal
magnet => Bo
- uniform (<4 ppm homogeneity)
- superconductive magnet
B0
•
B0 => net magnetization M0 (prop. to p density) //B0
•
RF on => Spin Flip => Transverse magnetization
•
RF off => relaxation [T1, T2 time const]
body RF coil
(transmitter)
local RF coil
(receiver)
Chiara Casella
M0 , T1, T2 are tissue dipendent !!! - 1 -
06.05.2015
Complementarity of PET and MRI
PET
map of radioactive tracer concentr.
functional
excellent sensitivity
molecular information
Chiara Casella
MRI
map of the local transverse magnetization of the H nuclei
morphological
excellent resolution
soft tissue contrast
-7-
06.05.2015
Complementarity of PET and MRI
PET
map of radioactive tracer concentr.
functional
excellent sensitivity
molecular information
MRI
map of the local transverse magnetization of the H nuclei
morphological
excellent resolution
soft tissue contrast
PET/MRI
=
+
Chiara Casella
-7-
06.05.2015
Why PET / MRI ?
1. MRI as anatomical counterpart for PET
Clear since the beginning of PET developments :
- huge potential of PET is being quantitative
- but need for anatomical information
Chiara Casella
-8-
06.05.2015
Why PET / MRI ?
1. MRI as anatomical counterpart for PET
Clear since the beginning of PET developments :
- huge potential of PET is being quantitative
- but need for anatomical information
=> PET / CT
Towsend et al (~ 2000)
• huge clinical impact
• a revolution in medical imaging
•
CT : Computed Tomography
‘x-rays in all projections’
=> why not PET / MRI ??
PET/MR was introduced even a
few years before PET/CT
because PET/CT is much simpler than PET/MRI !!
still is an active field of research
became quickly a commercial device
Chiara Casella
-8-
06.05.2015
PET/CT vs PET/MR
PET/CT
Advantages
- high soft-tissue contrast
- no additional dose
- reduction in positron range
=> higher spatial resol.
Limitations
- no soft-tissue contrast (brain)
- important additional dose (kids)
- possibility of simultaneous acquisition
=> time correlation, organs movements
- by definition: sequential
But...
big technical challenges :
Advantages
- simple!
- attenuation correction ‘for free’ =>
quantification!
Chiara Casella
PET/MRI
interference
geometrical constraints
complication in the att. corr.
-9-
06.05.2015
Why PET / MRI ?
2. functional capabilities of MRI (fMRI)
- MR can provide functional information (beside anatomical)
- complementarity with PET
- two examples :
[1] MRS (Spectroscopy)
- study tissue metabolism with 13C-labelled substrates
- MRS: high chemical specificity in identifying different metabolites
- MRS: low sensitivity (or interference with methabolism processes)
if 11C -labelled => MRS + PET
[2] CBF - Cerebral Blood Flow
- importance of constant delivery of oxygen in the brain
- CBF mechanisms are not yet completely understood
- CBF used as surrogate of neural activity in MRI => functional MRI
if 15O-H2O => fMRI + PET
t1/2(O-15) ~ 2 mins
changes of CBF up to 20% in time scales of seconds
=> high temporal resolution needed
Chiara Casella
- 10 -
06.05.2015
PET / MRI
1. MRI as anatomical counterpart for PET
2. complemetary functional capabilities of both modalities
PET / MRI > PET + MRI
and this is particularly true when :
- simultaneous
- dynamic
- in the pre-clinical field
technically difficult - but possible
Chiara Casella
- 11 -
06.05.2015
Possible because of the revolution in photodetection
PMT
high gain
good timing
not MR compatible
APD (Avalanche Photo Diodes)
insensitive to magnetic field / compact /
low gain
=> worse timing perfs
=> need of very low noise FE electronics
Kobe City College, Osaka University
fibers + PS-PMT
Axial ~ 0.5 cm
UC Davis, California
University of Cambridge APD
Axial ~ 1.9 cm
short fibers + APD
Axial ~ 1.2 cm
split magnet
fibers + PMT
Axial ~
7 cm
Chiara
Casella
University of Tuebingen,
Germany relevant examples of pre-clinical simultaneous PET/MRI that have been
used for in-vivo analysis
- 12 -
06.05.2015
Possible because of the revolution in photodetection
PMT
high gain
good timing
not MR compatible
APD (Avalanche Photo Diodes)
insensitive to magnetic field / compact /
low gain
=> worse timing perfs
=> need of very low noise FE electronics
SiPM
insensitive to magnetic field / compact
gain ~ PMT
excellent timing
Kobe City College, Osaka University
fibers + PS-PMT
Axial ~ 0.5 cm
UC Davis, California
University of Cambridge APD
Axial ~ 1.9 cm
short fibers + APD
Axial ~ 1.2 cm
split magnet
fibers + PMT
Axial ~
7 cm
Chiara
Casella
University of Tuebingen,
Germany relevant examples of pre-clinical simultaneous PET/MRI that have been
used for in-vivo analysis
- 12 -
06.05.2015
Trends in pre-clinical PET/MR
Trends:
- larger FOV
- higher sensitivity
- better spatial resol.
SiPM
- with SiPM
Chiara Casella
- 13 -
06.05.2015
Goal of the SAFIR project
• PET insert for MRI
• simultaneous pre-clinical imaging (perfectly time/space correlated)
• DYNAMIC PET/MRI ON TIME SCALES OF A FEW SECONDS
•
Target user of the detector:
IBT (Institute of Biomedical Engineering)
ETH/UniZh
Group Prof. Bruno Weber
neuroscience; pre-clinical multi-modal imaging;
expertise in MRI and hybrid image
•
Magnet :
Bruker BioSpin 70/30 USR MR system
- 7T - 30 cm inner bore (w/o gradient coil)
- already existing and commissioned at
ETH Small Animal Imaging Center
- dedicated lab room with direct tubing
connection to the cyclotron hall
Chiara Casella
- 14 -
06.05.2015
gradient coil
SAFIR detector requirements
[1] scintillators + photodetectors (conventional PET detector approach)
[2] geometry : 120mm inner / 200mm outer diameter
[3] dynamic PET with ultra-short acquisition
40 mm
120 mm
20
0
m
m
magnet (300 mm bore)
[4] spatial resolution ~ 2 mm
[5] mri-compatibility
Chiara Casella
- 15 -
06.05.2015
gradient coil
SAFIR detector requirements
40 mm
120 mm
20
[1] scintillators + photodetectors (conventional PET detector approach)
0
m
[2] geometry : 120mm inner / 200mm outer diameter
[3] dynamic PET with ultra-short acquisition
m
magnet (300 mm bore)
few sec’s acquisitions
high sensitivity ~ 10%
=>poor statistics - poor image quality =>
50 kcounts
500 kcounts
high injected activities
up to ~ 500 MBq [standard pre-clinical ~ 50 MBq]
readout and DAQ system
Randoms contribution!
no deadtime and no pileup
small coincidence window (<ns)
excellent time resolution ~ 300 ps FWHM
~ 10 kHz/mm2
~ 40 kHz / channel
~ 16000 channels
[4] spatial resolution ~ 2 mm
[5] mri-compatibility
Chiara Casella
1:1 coupling xtal/SiPM
- 15 -
06.05.2015
SAFIR detector
sketch of 1/2 detector
~ 1m
~ 150 - 180 mm
radial arrangement of crystal matrices with
1:1 coupling to SiPM arrays
LSO-type (LYSO, LSO:Ca...) crystal matrices
matrices 8x8 arrangement
ring structure / several modules per ring
exact size of the crystals / layout for the detector heads: to be finalized for the full detector
=> not yet final sizes given here!
Chiara Casella
- 16 -
06.05.2015
for the prototype
SAFIR first prototype ring
fixed size of the crystal:
(2.1 x 2.1 x 12) mm3
- one full ring
- using commercially available components
- procurement ongoing
- planned by end 2015
arrays 8x8
3M ESR foil optical separator
coupling to SiPM with optical glue
- 24 modules
- 1536 channels
[x ~10 rings for the full SAFIR]
200 mm
readout ASIC
TOFPET or STiC
front-end board
to be constructed
crystals array
few producers / xtal types considered
SiPM array
Hamamatsu S12893-0808PA-50
Chiara Casella
- 17 -
mechanical structure for the full
SAFIR detector
06.05.2015
Timeline of the project
•
•
•
early discussions
first interactions IBT
goal understanding
2013
phase 0
2014-2015
phase I
•
•
•
•
•
•
Chiara Casella
components evaluation
(xtals/ SiPM/ FE readout chip)
finalization of the design of
the first prototype ring
first simulations of the
detector
build image reconstruction
framework (static)
feasibility studies
performance prediction
2015-2016
phase II
•
•
•
first ring prototype
construction
commissioning
operation
optimization of the detector
design (for the full scanner)
4D reconstruction software
- 18 -
>2016
phase III
•
full scanner with optimized
design
06.05.2015
Timeline of the project
•
•
•
early discussions
first interactions IBT
goal understanding
2013
phase 0
2014-2015
phase I
•
•
•
•
•
•
Chiara Casella
components evaluation
(xtals/ SiPM/ FE readout chip)
finalization of the design of
the first prototype ring
first simulations of the
detector
build image reconstruction
framework (static)
feasibility studies
performance prediction
2015-2016
phase II
•
•
•
first ring prototype
construction
commissioning
operation
optimization of the detector
design (for the full scanner)
4D reconstruction software
- 18 -
>2016
phase III
•
full scanner with optimized
design
06.05.2015
SAFIR Simulations
native Geant4 simulations
•
simulated ‘ideal’ geometry :
• crystals : (2.1 x 2.1 x 12) mm3
• 0.1 mm gap
• continuous rings geometry
• no module structure
• axial length = 200 mm (91 ‘rings’)
• 180 xtals/ring => total 16380
•
•
•
•
ΔE/E ~ 20% FWHM (gaussian)
Gaussian time resolution - adjustable parameter
custom coincidence sorter
sources : point-like + phantoms
from simulations:
- Noise Equivalent Count Rate (NECR)
- sensitivity
- spatial resolution
Chiara Casella
according to NEMA standard (NU 4-2008)
standardized methodology for evaluating the
performance of a scanner
- 19 -
06.05.2015
NECR (Noise Equivalent Count Rate)
• figure of merit of a PET scanner
• rate of true coincidences normalized
TRUE
SCATTER
RANDOM
to the total rate of events
NECR = T2 / (T+S+R)
•
higher NECR value => higher ratio
of good events (T) to the overall
detected events (T, R, S) i.e. S/N
TRUE
larger activity peak value =>
capability to handle higher activities
NECR (S=0)
NECR with 10% Scatter fraction
(S = 0.1 T)
RANDOM
Chiara Casella
activity [MBq]
- 20 -
mouse
phantom
for NECR
definition
70 mm
25 mm
rates [Mcps]
•
F-18
polyethilene
06.05.2015
NECR (Noise Equivalent Count Rate)
• impact of time resolution on NECR (at optimized coincidence window)
CRT = Coincidence Time Resolution
Dead-Time = 0
Pileup = 0
i.e. no readout modelled
NECR ~ 14 MHz
ΔΕ/Ε = 20% FWHM
Energy window = [350,650] keV
500 MBq activity
NECR ~ 12 MHz
only ‘golden’ coinc. events included
10% scatter fraction
Chiara Casella
- 21 -
06.05.2015
NECR comparison with state-of-the-art PET scanner
Inveon pre-clinical PET scanner (Siemens) - microPET
-
stand-alone PET
axial FOV = 12.7 cm
LSO crystals : (1.5 x 1.5 x 10) mm3 each
PS-PMT (through light guide)
3.4 ns coincidence window
measured!
Costantinescu, 2009
Chiara Casella
- 22 -
06.05.2015
NECR comparison with state-of-the-art PET scanner
Inveon pre-clinical PET scanner (Siemens) - microPET
-
stand-alone PET
axial FOV = 12.7 cm
LSO crystals : (1.5 x 1.5 x 10) mm3 each
PS-PMT (through light guide)
3.4 ns coincidence window
NECR [Mcps]
SAFIR-like detector
measured!
Costantinescu, 2009
with CRT’s ~ few 100’s ps
NECR ~ x7-8 Inveon_NECR
CRT = 3.4 ns
act [MBq]
Chiara Casella
- 22 -
06.05.2015
Sensitivity
i.e. N_detected_coincs / N_annihilations
high solid angle coverage (~ 85%) => Excellent sensitivity
S_peak ~ 12%
S_average ~ 10.6 %
defined according to NEMA
- NEMA phantom : 1cm3 acrylic with 22-Na point source at the center
- low activity (Act = 100 kBq)
- at different axial distances
Chiara Casella
- 23 -
06.05.2015
Spatial resolution
Note:
(1.5 x 1.5 x 12)mm3 xtal size
i.e. not nominal
Resolution
< 1.5 mm FWHM (at center)
~ 2 mm FWHM (average)
(expected to get a bit worse for
the 2.1 mm crystals config)
-
NEMA phantom : 1cm3 acrylic with 22-Na point source at the center
low activity (Act = 100 kBq)
at different axial distances
spatial definition according to NEMA requires image reco algorithms
Chiara Casella
- 24 -
06.05.2015
Phantoms image reconstruction
simulated (input)
Derenzo phantom - geometry : 2.1 mm crystals
1.2 mm
1.0 mm
2.4 mm
1.6 mm
2.4 mm
4.0 mm
1.2 mm
reconstructed
3.2 mm
3.2 mm
2.4 mm
Chiara Casella
1.6 mm
4 mm
3.2 mm
1 mm
=> Image reconstruction :
- up to 1.6 mm structures are ~ resolvable
- 25 -
06.05.2015
Phantoms image reconstruction
Derenzo phantom
a) no background
(i.e. all activity in the spheres)
Total activity : 500 MBq
Acquisition duration: fraction of 1 second
b) with background (456MBq in background)
465 MBq (bkg) + 35 MBq (spheres)
Chiara Casella
- 26 -
497 MBq (bkg) + 3 MBq (spheres)
06.05.2015
Laboratory activities - characterization measurements
Three major activities ongoing :
1) SiPM / crystals analogue characterization
2) Timing performance (specially focused on
coincidence timing resolution: CRT)
3) Operation of existing readout ASIC chips
with special focus on rate and timing
performance
Chiara Casella
- 27 -
06.05.2015
Lab equippement
(at CERN Prevessin Blg.892)
SiPM :
- single ones
- arrays
- different prods
- different types
crystals :
- single ones
- matrices
- different prods
- different types
Analogue readout chain
- custom made amplifiers
- bias system
- VME QDC acquisition
Digital SiPM (Philips)
- tool to measure CRT in direct comparison
Readout ASICs
- TOFPET
- STIC
Chiara Casella
- 28 -
06.05.2015
Analogue characterization of SiPM / Xtal
22Na source
Peltier cooling unit
temperature sensor
thermal box
+ light shielding
SiPM
3D printed crystal holder
different types of runs :
- LED light (few pe’s) without xtal
LED
- 22-Na source with xtals
- intrinsic radioactivity of LYSO
blocks with crystals
Chiara Casella
LYSO crystals [2x2x2]cm3
- 29 -
06.05.2015
Analogue characterization of SiPM / Xtal
63 keV
LED
(no crystal)
202 keV
511 keV
22Na
(with crystal)
307 keV
intrinsic radioact.
(with crystal)
1.27 MeV
ADC counts (higher gain)
ADC counts
ADC counts
Calibration
[ADC counts / pe]
Chiara Casella
- 30 -
06.05.2015
Analogue characterization of SiPM / Xtal
nr photoelectron vs energy
MPPC 8
MPPC 73
MPPC 23
XTAL :
[1.5 x 1.5 x 12] mm3 with ESR wrapping
SiPM :
[3x3] mm2
Hamamatsu
25 μm cell size
50 μm cell size
50 μm cell size
low cross talk
[with trenches]
Light yield at the photopeak
AGILE LYSO
~ 2000
~ 1700
~ 1400
SIPAT LYSO[*]
~ 1600
~ 1400
~ 1000
SIPAT LYSO:Ca
~ 1300
[*] = plots
Chiara Casella
~ 1100
~ 900
~ 1000 - 1500 pe’s @ 511 keV
different saturation response depending on the adopted SiPM type
- 31 -
06.05.2015
Timing properties of different crystals
- different pairs of crystals
- tested with the same readout setup: digital SiPM (Philips)
- direct comparison of coincidence time resolution
25% impr. wrt undoped
20%
30%
improvement wrt bare
Chiara Casella
- 32 -
06.05.2015
Readout ASIC chip
Out of the many SiPM readout chips options :
[*] also used at ETH for
the mu3e experiment
• ToFPET ASIC (from LIP - Lisbon)
• STiC 3.1 ASIC (from KIP - Heidelberg) [*]
Both developed within the Endo-TOF-PET-us collaboration
- clinical
- Time of Flight !
Stringent requirements (shared identically by SAFIR)
- SiPM and crystals readout
- measure time and energy
- excellent timing resolutions CRT ~ 200 ps FWHM
- large channel density
CRT ~ 300 ps FWHM : state of the
art for clinical TOF-PET full systems
- low power consumption
+ high rate capabilities (specifically for SAFIR)
X
X = c/2 Δt
Chiara Casella
- 33 -
✸
t
2
Δt
X
100 ps
1.5 cm
300 ps
4.5 cm
no TOF
t1
with TOF
06.05.2015
ToF PET and STiC
Energy and timing measurement through Time Over Threshold (ToT) logic
HIGH!
energy thr
dark count rejection
TOFPET [x2]
LOW (~ 0.5 pe)!
to optimize CRT
T
evaluation kits
E
- 64 channels /ASICs
- analogue front-end (ampl, discr.) + digitization / LVDS output
- same logic, different implementation
STIC :
• TDC
[50 ps time tick]
• linearized ToT method =>
improved ΔE/E
• differential at the input stage
• 30 mW/channel
Chiara Casella
STIC
[x2]
TOFPET :
•
•
analogue TDC : TACs / ADC +
multi-buffer approach to
derandomize the input rate
10 mW/channel
- 34 -
06.05.2015
ToT spectra (arrays)
Na-22 source - no coinc
4x4 matrix (3.1 x 3.1 x 12) mm3 /xtal
n.counts
n.counts
n.counts
ToT [ns]
ToT [ns]
ToT [ns]
n.counts
ToT [ns]
ToT [ns]
n.counts
n.counts
ToT [ns]
n.counts
STIC
n.counts
TOFPET
ToT [ns]
ToT [ns]
- The max validation THR for TOFPET is too low (~ 20-25 pe)
- Significant bandwidth occupied by low energy noise
- low energy noise? => cross-talk among channels of the array
Chiara Casella
- 35 -
06.05.2015
CRT performance - single channels
- cut ToT at the photopeak
- build coincidence events
- measure CRT
crystals LYSO (1.5x1.5x12)mm3
Note : No grease, no wrapping
TOFPET
STIC
CRT FWHM ~ 480 ps
( best ~ 410 ps )
Chiara Casella
- 36 -
2 channels
CRT FWHM ~ 380 ps
06.05.2015
High rate test (TOFPET only so far)
motherboard
syringe filled with 18-F (high activity)
Sensors: Hamamatsu S12642-0404PB-50(X)
Matrices: Hilger matrix – (3.1 x 3.1) mm2
High rate test with high activity tracer
At UniZh hospital (daily 18-F prod.)
Dec 2014
Up to 500 MBq used
Different load configurations
(single channel, 1+1 matrix, 1+4
matrices)
variable distance face to face
(nominal = 120mm)
Chiara Casella
mezzanine boards
(hosting the chip)
- 37 -
06.05.2015
inc
re
a
sin
ga
cti
vit
y
High rate test : CRT performance
• deterioration of the timing resolution with the activity
• CRT (extrapolated at Act = 0 ) ~ 670 ps FWHM
[out of specs!!!]
• to be investigated further !!!
Chiara Casella
- 38 -
06.05.2015
Hardware activities - Short term plan
Focusing specifically on the first prototype ring:
• SiPM arrays : to be purchased
• Crystals :
• LYSO Ca-codoped
• a few SIPAT:Ca-ESR matrices ordered
• verify performance
• place the order
• STIC or TOFPET ?
• new bias system (compensated by the voltage drop)
• high rate tests with both chips in Zurich
• decision on which solution we use
• place the order
• develop readout board PCB
Chiara Casella
- 39 -
06.05.2015
Conclusions
• PET instrumentation : rapidly evolving scenario
• Simultaneous PET/MRI technology is now mature
• Overall trend in pre-clinical developments : improving sensitivity / improving spatial resolution
• SAFIR : improving temporal resolution (i.e. short acquisitions duration at high repetition rate) for
dynamic simultaneous PET/MRI - large impact in biomedical hybrid imaging !
• Unconventional PET detector
- up to 500 MBq activity
- excellent time resolution (w/o being a TOF system...)
• Demonstration of the concept (through simulations) :
- improved NECR (~ x7-8 wrt state of the art PET scanners)
- high sensitivity (~ 10%)
- good spatial resolution (~ 2 mm)
• First reconstructions : preliminary but promising
• Hardware works ongoing for the choice of the components :
- SiPM arrays
- crystal matrices
- readout chip ASIC
• First ring with commercial devices planned end2015 / mid2016!!
Chiara Casella
- 40 -
06.05.2015
Conclusions
• PET instrumentation : rapidly evolving scenario
• Simultaneous PET/MRI technology is now mature
• Overall trend in pre-clinical developments : improving sensitivity / improving spatial resolution
• SAFIR : improving temporal resolution (i.e. short acquisitions duration at high repetition rate) for
dynamic simultaneous PET/MRI - large impact in biomedical hybrid imaging !
• Unconventional PET detector
- up to 500 MBq activity
- excellent time resolution (w/o being a TOF system...)
• Demonstration of the concept (through simulations) :
- improved NECR (~ x7-8 wrt state of the art PET scanners)
- high sensitivity (~ 10%)
- good spatial resolution (~ 2 mm)
• First reconstructions : preliminary but promising
h !!
c
u
e
m
m
o
d
c
an to
e
r
o
m
• Hardware works ongoing for the choice of the components :
- SiPM arrays
- crystal matrices
- readout chip ASIC
• First ring with commercial devices planned end2015 / mid2016!!
Chiara Casella
- 40 -
06.05.2015
Collaboration
Institute for Particle Physics - ETH :
R. Becker, C. Casella, D. Di Calafiori, G. Dissertori, L. Djambazov, M. Droge, C. Haller,
A. Howard, K. Kramer, J. Fischer, W. Lustermann, U. Roeser, Q. Wang
expected to join soon: M. Ito (post-doc) , P. Katheri (PhD)
Institute for Biomedical Engineering - ETH:
M. Rudin (and group)
Institute for Pharmacology and toxicology - University Zurich :
B. Weber (and group)
University of Valencia, IFIC :
J. Oliver
Centre Physique Particules Marseille (CPPM) :
J-P. Cachemiche, C. Morel
Chiara Casella
- 41 -
06.05.2015