1. Inorganic Scintillators in Medical-imaging Detectors C. W. E
Inorganic Scintillators in Medical-imaging Detectors C.W.E. van Eijk Amsterdam, 9 September 2002

2. Efficiency Inorganic scintillator
Radiation in Medical Imaging
Energies
X-ray imaging Mammography kVp, ~18 keV
Radiography, chest kVp
Fluoroscopy kVp
X-ray CT kVp
Nuclear medicine Scintigraphy keV
SPECT keV
PET keV
Modality
emission
transmission
Efficiency Inorganic scintillator

3. Interventional Radiology
Fluoroscopy - Real time - Low dose
ImageIntensifier
Mobile C-arm system for
full surgical and minimally-invasive procedures
From: Philips Medical Systems BV300 series

4. Transjugular Intrahepatic Portosystemic Shunt (TIPS)
Interventional Radiology
minimally-invasive procedure
Transjugular Intrahepatic Portosystemic Shunt (TIPS)

5. Flat panel detector - Amorphous silicon
Interventional Radiology
Flat panel detector - Amorphous silicon
Columnar CsI:Tl
ADC
readout
addressing
2k x 2k
40 x 40 cm2
also for
radiography
Flat X-ray Detectors for
Medical Imaging
Dr. Michael Overdick
Session 5
From: Philips, Aachen

6. Flat panel detector - Amorphous silicon
Interventional Radiology
Flat panel detector - Amorphous silicon
Photodiode
signal depends on:
scintillator light yield
optical coupling
spectral matching
diode efficiency
From: Philips, Aachen

7. Interventional Radiology
CsI:Tl
pillar growth induced by evaporation technique
crack structure
focussing of light
>500 µm layers
high MTF
From: Philips, Aachen

8. X-ray Computed Tomography
Ceramic
scintillators +
photodiodes
~ 1 k x
1 mm
~ 16 x 1 mm
X-ray source
(rotating) +
1-D or 2-D
position-sensitive
detector
X-ray
fan beam
E. Hell et al, NIM A 454 (2000) 40-48

9. From: W.A. Kalender, CT, 2000, MCD Verlag
X-ray Computed Tomography
1974:
80 x 80 pixels
slices of 13 mm spacing
2000:
1024 x 1024 pixels
spiral scanning
From: W.A. Kalender, CT, 2000, MCD Verlag

10. X-ray Computed Tomography
Ceramic Scintillators 4
density ρZ
light yield dec. time afterglow wavel. max.
(g/cm3) (106)
(phot./MeV) (μs) (% after (nm)
3/100 ms)
CdWO4
7.9
,000
< 0.1/
0.02
495
Bi4Ge3O12
(BGO) ,
CsI:Tl
4.5 ,
> >2/ -
Gd2O2S:Pr,Ce,F , < 0.1/<
Gd2O2S:Pr (UFC) , /
Y1.34 Gd0.60 O3:(Eu,Pr) , /<
(Hilight)
Gd3Ga5O12:Cr,Ce
7.1
,000
140
< 0.1/0.01
730
Lu2O3:Eu,Tb
, > > 1/

11. X-ray Computed Tomography
Afterglow in scintillators
1 angle per < ms
From: W.A. Kalendber, CT, 2000, MCD Verlag

12. Positron Emission Tomography
Detector ring
(inner diam. ~ 0.8 m)
Collinearly emitted 511 keV quanta detected in coincidence
Detectors
BGO + PMT
Bi4Ge3O12
Radiopharmaceutical
β+ emitter

13. Positron Emission Tomography
PET systems Siemens-CTI

14. PET Detector Block Efficiency BGO detector block A B 4 PMTs C D
8 x 8 columns
30 mm
of 6 x 6 x 30 mm3
Bi4Ge3O12
Efficiency

15. Positron Emission Tomography: 2D & 3D
Septa
Septa removed
2D D

16. Positron Emission Tomography
3D PET
Increase Random coincidences
~ N2singlesτ
Time resolution
Energy resolution
Light yield
Decay time
Non-proportionality
From: G. Muehllehner et al. & SCINT 2001

17. Positron Emission Tomography
PET Scintillators
 /μ 511 keV light yield  
(g/cm3) (mm) /PE (%) (photons/MeV) (ns) (nm)
Bi4Ge3O (BGO) / ,
Lu2SiO5:Ce (LSO) / ,
Gd2SiO5:Ce (GSO) / 26 8,
LuxY1-xAlO3:Ce (LuAP) / ,
Lu2Si2O7:Ce (LPS) / ,
Energy resolution poor

18. photomultiplier readout
Scintillators Energy Resolution
LaCl3:Ce(10%)
ΔE/E = 3.1 %
600
700
200
400
800
1000
1200
1400
1600
LaCl 3
:Ce
counts
energy [keV]
E (keV)
COUNTS
photomultiplier readout
Hamamatsu R1791
E.V.D. van Loef et al Appl. Phys. Lett. 77 (2000) 1467

19. incorrect Line of Response
PET basics: Position resolution
Efficient
High position resolution
parallax error or
radial elongation
Off centre:
incorrect Line of Response
Remedy:
Depth of Interaction
measurement
DOI

20. PET: Depth of Interaction in HRRT
PMTs
Light guides
LSO scintillators
Lu2SiO5:Ce
7.5 x 2.1 x 2.1 mm3
Different decay times
in the two layers 
Different pulse shape  DOI
PMTs
From: D.W. Townsend, C. Morel presented at SCINT 2001
K. Wienhard et al IEEE NSS/MIC CDROM

21. Pulse shape discrimination
PET: DOI
Crystal Clear
Depth of Interaction
LSO
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

22. Positron Emission Tomography
Multi modality
PET + MRI
Blood flow changes under
speech activation (red)
Tumor (green)
From: Klaus Wienhard
MPI für Neurologische Forschung, Köln

23. 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 detectors
APDs
Silicon drift detectors
C.W.E. van Eijk
Inorganic scintillators in medical imaging
Phys.Med.Biol. 47 (2002) R85 - R106