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

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Inorganic Scintillators in
Medical-imaging DetectorsC.W.E. van Eijk
Amsterdam, 9 September 2002
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Radiation in Medical Imaging
Modality
Energies X-ray imaging Mammography
25 kVp, 18 keV Radiography, chest
150 kVp Fluoroscopy 150 kVp X-ray
CT 150 kVp Nuclear medicine
Scintigraphy 80 - 140 keV SPECT
60 - 511 keV PET 511 keV
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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
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Interventional Radiology
minimally-invasive procedure
Transjugular Intrahepatic Portosystemic Shunt
(TIPS)
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Interventional Radiology
Flat panel detector - Amorphous silicon
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
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Interventional Radiology
Flat panel detector - Amorphous silicon
Photodiode

• signal depends on
• scintillator light yield
• optical coupling
• spectral matching
• diode efficiency

From Philips, Aachen
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Interventional Radiology
CsITl

• pillar growth induced by evaporation technique
• crack structure
• focussing of light
• gt500 µm layers
• high MTF

From Philips, Aachen
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X-ray Computed Tomography
E. Hell et al, NIM A 454 (2000) 40-48
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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
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X-ray Computed Tomography
Ceramic Scintillators
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density

?Z
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 lt 0.1/
495


0.02




















Bi4Ge3O12
(BGO) 7.1 227 9,000
0.3 480


CsITl
4.5
38 66,000 8
-
gt 6 gt2/0.3 550
Gd2O2SPr,Ce,F 7.3 103
35,000 4 lt 0.1/lt 0.01
510
Gd2O2SPr (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/lt 0.01 610
















(Hilight)







Gd3Ga5O12Cr,Ce
7.1
58 40,000
140
lt 0.1/0.01
730






Lu2O3Eu,Tb
9.4 211 30,000 gt 1000 gt 1/0.3
610







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X-ray Computed Tomography
Afterglow in scintillators
1 angle per lt ms
From W.A. Kalendber, CT, 2000, MCD Verlag
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Positron Emission Tomography
Detector ring (inner diam. 0.8 m)
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Positron Emission Tomography
PET systems Siemens-CTI
http//www.epub.org.br/cm/n01/pet/pet_hist.htm
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PET Detector Block
Efficiency
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Positron Emission Tomography 2D 3D
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Positron Emission Tomography
3D PET
Increase Random coincidences
N2singlest
Time resolution
Energy resolution
Light yield Decay time Non-proportionality
From G. Muehllehner et al. SCINT 2001
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Positron Emission Tomography

PET Scintillators
? 1/µ 511 keV light yield
? ? (g/cm3) (mm) /PE
() (photons/MeV) (ns) (nm)
Bi4Ge3O12 (BGO) 7.1 11.6 / 44
9,000 300 480 Lu2SiO5Ce (LSO)
7.4 12.3 / 34 26,000 40
420 Gd2SiO5Ce (GSO) 6.7 15 / 26 8,000
60 440 LuxY1-xAlO3Ce (LuAP) 8.3 11.0
/ 32 11,000 18 365 Lu2Si2O7Ce
(LPS) 6.2 14.5 / 29 20,000 30
380
Energy resolution poor
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Scintillators Energy Resolution
LaCl3Ce(10)
?E/E 3.1
photomultiplier readout Hamamatsu R1791
E.V.D. van Loef et al Appl. Phys. Lett. 77
(2000) 1467
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PET basics Position resolution
Efficient High position resolution
Remedy Depth of Interaction measurement DOI
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PET Depth of Interaction in HRRT
PMTs
Light guides
LSO scintillators
Lu2SiO5Ce
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 2000 IEEE NSS/MIC CDROM
17 280
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PET DOI
Crystal Clear
Depth of Interaction
LuAP
LSO
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
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Positron Emission Tomography
Multi modality PET MRI
Blood flow changes under speech activation
(red) Tumor (green)
From Klaus Wienhard MPI für Neurologische
Forschung, Köln
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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