ENU 6659 Intro
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Transcript of ENU 6659 Intro
Nuclear Medicine
Imaging of (injected) radio-labeled pharmaceuticals
Emission Tomography
3D nuclear medicine imaging
• SPECT: single photon emission computed tomography
• PET: positron emission tomography
# PET systems / pop. # PET systems / pop. millionmillion
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CA TX NY FL IL PA OH MI GA NJ NC
IMV 2005/2006 Market Summary ReportIMV 2005/2006 Market Summary Report
•Bone scan
•Tc-99m
•anterior/posterior views
Nuclear medicine (PET and SPECT) provides images related to the body’s
Function (physiology)
compared with x-ray images that are related to the body’s
Anatomy (physical properties)
Brain metabolism imaging w/ PET
Normal
Perfusiondefect
Myocardial Perfusion Imaging w/ SPECT
PET Brain ImagesPET Brain Images
Alzheimer’s Disease with Alzheimer’s Disease with PETPET
normal
diseased
Molecular Imaging
moles / min / ml of tissue
F-18 Fluoro-deoxy-glucose F-18 Fluoro-deoxy-glucose (FDG)(FDG)
(PET metabolism tracer)(PET metabolism tracer)
Advances in SPECT gamma camerasAdvances in SPECT gamma cameras
1980 1985 1990
dual head (fixed 180)
single head triple head (fixed 120)
1990 1995 2000
Advances in SPECT gamma camerasAdvances in SPECT gamma cameras
dual head (fixed 90)
dual head (variable angle)
triple head (variable angle)
SPECT InstrumentationSPECT Instrumentation
transmission
emission
No collimator
transmission
emission
With collimator
Annihilation Annihilation (simple)(simple)
conservation of momentum:
before: system at rest; momentum ~ 0
after: two photons created; must have same energy and travel in opposite direction.
conservation of energy
before: 2 electrons, each with a rest mass of 511keV
after: 2 photons, each with 511keV.
decay via positronemission
electron/positronannihilation
annihilationphoton
annihilationphoton
PET PhysicsPET Physics
Coincidence EventCoincidence Event
Annihilation location
Time-of-Flight PETTime-of-Flight PET
Annihilation location
d1
d2
t = (d2-d1)/c
t
x = t·c/2
Detector midpointx
= 2x/c
PET InstrumentationPET Instrumentation
PET/CTPET/CT
PET
PET/CT
ET Detectors (i.e. Cameras)ET Detectors (i.e. Cameras)
Needs: High count rate capability (short T1/2 emitters)
Efficiency (511 keV) Energy resolution (scatter rejection)
Low cost
Detector MaterialsDetector Materials
Scintillators• NaI• BGO• LSO
Semiconductors• CdZnTe
Cardiac perfusion imaging:Cardiac perfusion imaging: Attenuation effectsAttenuation effects
Without attenuation correctionWith attenuation correction