T IRI-ST Delft U TU Delft IRI-ST Inorganic Scintillators in Medical-imaging Detectors C.W.E. van Eijk Amsterdam, 9 September 2002
T IRI-STDelft U TU Delft IRI-ST
Inorganic Scintillators in
Medical-imaging Detectors
C.W.E. van Eijk
Amsterdam, 9 September 2002
T IRI-STDelft U TU Delft IRI-ST
Radiation in Medical Imaging
EnergiesX-ray imaging Mammography 25 kVp, ~18 keV
Radiography, chest 150 kVpFluoroscopy 150 kVpX-ray CT 150 kVp
Nuclear medicine Scintigraphy 80 - 140 keVSPECT 60 - 511 keVPET 511 keV
Efficiency Inorganic scintillator
Modality
emission
transmission
T IRI-STDelft U TU Delft IRI-ST
From: Philips Medical Systems BV300 series
Mobile C-arm system for full surgical and minimally-invasive
procedures
Interventional RadiologyFluoroscopy - Real time - Low dose
ImageIntensifier
T IRI-STDelft U TU Delft IRI-STTransjugular Intrahepatic Portosystemic Shunt (TIPS)
Interventional Radiologyminimally-invasive procedure
T IRI-STDelft U TU Delft IRI-ST
Flat panel detector - Amorphous silicon
also for radiography
Columnar CsI:Tl
ADCreadout
addressing
Interventional Radiology
From: Philips, Aachen
Flat X-ray Detectors for Medical Imaging
Dr. Michael Overdick
Session 5
2k x 2k40 x 40 cm2
T IRI-STDelft U TU Delft IRI-ST
signal depends on:– scintillator light yield– optical coupling – spectral matching– diode efficiency
400 500 600 700 8000,0
0,2
0,4
0,6
0,8
1,0
wavelength / nm
400 500 600 700 8000,0
0,2
0,4
0,6
0,8
1,0
CsI:Tla-Si:H
Photodiode
From: Philips, Aachen
Flat panel detector - Amorphous silicon
Interventional Radiology
T IRI-STDelft U TU Delft IRI-ST
pillar growth induced by evaporation technique– crack structure– focussing of light – >500 µm layers– high MTF
CsI:Tl
From: Philips, Aachen
Interventional Radiology
T IRI-STDelft U TU Delft IRI-ST
X-ray Computed Tomography
X-ray source(rotating)
+
1-D or 2-Dposition-sensitive detector(rotating)
X-ray fan beam(rotating)
+ Ceramicscintillators + photodiodes
~ 1 k x 1 mm
~ 16 x 1 mm
E. Hell et al, NIM A 454 (2000) 40-48
T IRI-STDelft U TU Delft IRI-ST
1974: 80 x 80 pixelsslices of 13 mm spacing
2000:1024 x 1024 pixelsspiral scanning
From: W.A. Kalender, CT, 2000, MCD Verlag
X-ray Computed Tomography
T IRI-STDelft U TU Delft IRI-ST
density ρZ 4 light yield dec. time afterglow wavel. max. (g/cm3) (106)
(phot./MeV) (μs) (% after (nm)
3/100 ms)
CdWO4 7.9 134 20,000 5 < 0.1/ 0.02 495
Bi4Ge3O12 (BGO) 7.1 227 9,000 0.3 480
CsI:Tl 4.5 38 66,000 8 - > 6 >2/0.3 550Gd2O2S:Pr,Ce,F 7.3 103 35,000 4 < 0.1/< 0.01 510
Gd2O2S:Pr (UFC) 7.3 103 50,000 3 0.02/0.002 510 Y1.34 Gd0.60 O3:(Eu,Pr)0.06 5.9 44 44,000 1000 4.9/< 0.01 610
(Hilight) Gd3Ga5O12:Cr,Ce
7.1
58 40,000
140 < 0.1/0.01
730 Lu2O3:Eu,Tb
9.4 211 30,000 > 1000 > 1/0.3 610
X-ray Computed Tomography
Ceramic Scintillators
T IRI-STDelft U TU Delft IRI-STFrom: W.A. Kalendber, CT, 2000, MCD Verlag
Afterglow in scintillators1 angle per < ms
X-ray Computed Tomography
T IRI-STDelft U TU Delft IRI-ST
Positron Emission Tomography
Detector ring (inner diam. ~ 0.8 m)
Collinearly emitted 511 keV quanta detected in coincidence
Radiopharmaceutical β+ emitter
DetectorsBGO + PMT
Bi4Ge3O1
2
T IRI-STDelft U TU Delft IRI-ST http://www.epub.org.br/cm/n01/pet/pet_hist.htm
PET systems Siemens-CTI
Positron Emission Tomography
T IRI-STDelft U TU Delft IRI-ST
PET Detector Block
AB
CD
4 PMTs
BGO detector block8 x 8 columns
30 mm
of 6 x 6 x 30 mm3
Bi4Ge3O12
Efficiency
T IRI-STDelft U TU Delft IRI-STFrom: G. Muehllehner et al. & SCINT 2001
Increase Random coincidences~ N2
singlesτ3D PET
Energy resolution
Time resolution
Positron Emission Tomography
Light yieldDecay timeNon-proportionality
T IRI-STDelft U TU Delft IRI-ST
Bi4Ge3O12 (BGO) 7.1 11.6 / 44 9,000 300 480Lu2SiO5:Ce (LSO) 7.4 12.3 / 34 26,000 40 420Gd2SiO5:Ce (GSO) 6.7 15 / 26 8,000 60 440LuxY1-xAlO3:Ce (LuAP) 8.3 11.0 / 32 11,000 18 365Lu2Si2O7:Ce (LPS) 6.2 14.5 / 29 20,000 30 380
1/μ 511 keV light yield
(g/cm3) (mm) /PE (%) (photons/MeV) (ns) (nm)
Positron Emission Tomography
PET Scintillators
Energy resolution poor
T IRI-STDelft U TU Delft IRI-ST
ΔE/E = 3.1 %
photomultiplier readoutHamamatsu R1791
LaCl3:Ce(10%)
Scintillators Energy Resolution
0 100 200 300 400 500 600 7000
200
400
600
800
1000
1200
1400
1600
1800
2000LaCl
3:Ce
coun
ts
energy [keV]
600 7000
200
400
600
800
1000
1200
1400
1600 LaCl3:Ce
coun
ts
energy [keV]
LaCl3:Ce
E (keV) E (keV)
COUN
TS
COUN
TS
E.V.D. van Loef et al Appl. Phys. Lett. 77 (2000) 1467
T IRI-STDelft U TU Delft IRI-ST
PET basics: Position resolutionEfficient High position resolution
parallax error orradial elongation
Off centre:
incorrect Line of Response
Remedy:Depth of Interactionmeasurement
DOI
T IRI-STDelft U TU Delft IRI-ST
PET: Depth of Interaction in HRRT
PMTs
LSO scintillators
Light guides
PMTs
7.5 x 2.1 x 2.1 mm3
From: D.W. Townsend, C. Morel presented at SCINT 2001K. Wienhard et al 2000 IEEE NSS/MIC CDROM 17 280
Lu2SiO5:Ce
Different decay timesin the two layers
Different pulse shape DOI
T IRI-STDelft U TU Delft IRI-ST
Depth of Interaction
LuAP APD array
Pulse shape discrimination
Saoudi et al IEEE Trans Nucl Sci 46(1999)462, also 479 Seidel et al IEEE Trans Nucl Sci 46(1999)485
LSO
PET: DOI CRYSTAL
CLEARCrystal Clear
T IRI-STDelft U TU Delft IRI-ST
From: Klaus Wienhard MPI für Neurologische Forschung, Köln
Blood flow changes under speech activation (red)Tumor (green)
Multi modality
PET + MRI
Positron Emission Tomography
T IRI-STDelft U TU Delft IRI-ST
Inorganic Scintillators in Medical-imaging Detectors
Conclusion Interest in further improvement of inorganic scintillators
Fundamental research
Especially for PET also Mammography PET
Small Animal PET
Use of new light detectorsAPDsSilicon drift detectors
C.W.E. van Eijk Inorganic scintillators in medical imagingPhys.Med.Biol. 47 (2002) R85 - R106