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New Scintillation Materials and Engineering for Medical Imaging. A.Gektin, B.Grinyov Institute for Scintillation Materials, Kharkov, Ukraine. Outlines: Material vs application Materials for different modalities Scintillators for SPECT&PET Last trends in detector engineering. - PowerPoint PPT Presentation
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T IRI-STDelft U Kharkov, Ukraine ISMA
A.Gektin, B.GrinyovInstitute for Scintillation Materials, Kharkov, Ukraine
New Scintillation Materials and Engineering for Medical Imaging
Outlines:
Material vs application
Materials for different modalities
Scintillators for SPECT&PET
Last trends in detector engineering
T IRI-STDelft U Kharkov, Ukraine ISMA
Radiation in Medical Imaging
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
Modality
emission
transmission
Two options: Anatomic and/or Functional Image
T IRI-STDelft U Kharkov, Ukraine ISMA
Scintillators for Medical Imaging
Material g/
cm3
Y, ph/MeV sc, ns sc, nm 1/ sc, MHz
Gd2O2S: Pr,Ce,F 7.34 40000 2100 580 0.4
CsI(Tl) 4.51 61000 900 565 1.0
CdWO4 7.9 19700 2000 495 0.5
ZnWO4 7.87 21500 22000 480 0.05
CaWO4 6.1 6000 600 430 1.7
Bi3Ge4O12 (BGO) 7.13 8200 300 505 3.3
Lu3Al5O12:Sc 6.7 22500 610 270 1.6
LuAlO3:Ce (LuAP) 8.34 11400 17+slow 365 58
Lu2SiO5:Ce (LSO) 7.4 27000 40 420 25
Lu2Si2O7:Ce (LPS) 6.23 30000 30 380 33
LuBO3:Ce 7.4 26000 39 410 26
NaI(Tl) 3.67 40000 230 415 4.3
T IRI-STDelft U Kharkov, Ukraine ISMA
X — Ray screens. Digital Radiography
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
From film to digital screen
50km – spatial resolution
Amorphous silicon
Spectral MatchingColumnar CsI:Tl
T IRI-STDelft U Kharkov, Ukraine ISMA
density light yield dec. time afterglow wavel. max.
(g/cm3)
(phot./MeV) (μs) (% after (nm)
3/100 ms)
CdWO4
7.9 20,000 5 < 0.1/ 0.02 495
Bi4Ge3O12 (BGO) 7.1 9,000 0.3 480
CsI:Tl 4.5 66,000 8 - > 6 >2/0.3 550
Gd2O2S:Pr,Ce,F 7.3 35,000 4 < 0.1/< 0.01 510
Gd2O2S:Pr (UFC) 7.3 50,000 3 0.02/0.002 510
Y1.34 Gd0.60 O3:(Eu,Pr)0.06 5.9 44,000 1000 4.9/< 0.01 610
(Hilight) Gd3Ga5O12:Cr,Ce
7.1
40,000
140 < 0.1/0.01
730
Lu2O3:Eu,Tb
9.4 30,000 > 1000 > 1/0.3 610
X-ray Computed Tomography
Ceramic Scintillators
T IRI-STDelft U Kharkov, Ukraine ISMA
SPECT: current standard practice (basic!)
• dual head acquisition
• filtered back projection
• gated cardiac acquisition
• dynamic acquisition (never)
• Chang attenuation correction (sometimes)
• measured transmission (available at few sites)
• iterative reconstruction (available but underutilized)
• scatter correction (limited use)
• motion correction (available but crude!)
• resolution compensation (not usually available)
• partial volume correction (what’s this?)
T IRI-STDelft U Kharkov, Ukraine ISMA
NaI(Tl) gamma cameras history
www.siemens.de
Dual head camera
Single head camera
high spatial resolution
scintimamography
single head camera
circular detector
1959
whole body imaging
90th
80th
70th
cylindrical detector
curve NaI(Tl) detector
dual head detector
dual head camera
single head camera
rectangular detector
2000th
21 century
SPECT tomography
Anger invention
prototype
coincidence measurement
T IRI-STDelft U Kharkov, Ukraine ISMA
From conventional to dedicated and dual mode SPECT systems
Last years SPECT upgrades
“Curve Plate”technology Cylindrical detector techique
light
out
put
A – slotting
B – no slots
x
Slotted scintillator
–– quantum
Coincidence mode detector
T IRI-STDelft U Kharkov, Ukraine ISMA
Opportunities for developmentMulti-modality imaging as a precursor for advanced analysis
T IRI-STDelft U Kharkov, Ukraine ISMA
Different Designs for the Same Application
Continuouscrystal
Partly pixilatedcrystal
Matrix + light guide
Dual mode (PET/SPECT) imaging system
Anger Logics
T IRI-STDelft U Kharkov, Ukraine ISMA
Underlying Principle of PET. (Positron Emission Tomography)
Detector ring diameter 0.8-0.9 m
Collimated 511 keV quanta detected in coincidence
T IRI-STDelft U Kharkov, Ukraine ISMA
PET Detector Design
T IRI-STDelft U Kharkov, Ukraine ISMA
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 Kharkov, Ukraine ISMA
New PET Developments DOI — Depth of Interaction
incorrect Line of Response
Depth of Interaction
LuAPAPD array
Pulse shape discrimination
LSO
Special resolution increase
T IRI-STDelft U Kharkov, Ukraine ISMA
New Scintillators. High Energy Resolution
0 100 200 300 400 500 600 7000
200
400
600
800
1000
1200
1400
1600
1800
2000
LaCl3:Ce
coun
ts
energy [keV]
600 7000
1000
1600
coun
ts
energy [keV]
LaCl3:Ce
LaCl3:Ce
LaCl3:Ce(10%)
ΔE/E = 3.1%
Energy resolution
Time resolution
Light yieldDecay timeNon-
proportionality
T IRI-STDelft U Kharkov, Ukraine ISMA
New Scintillation Materials and Engineering for Medical Imaging
Conclusions: Further improvement of scintillator is possible
Search and development of new scintillators are the base for imaging systems upgrade
Advance scintillation detector engineering is the option for new modality development (animal imaging, scintimammography, dedicated images)