Preliminary pinhole SPECT reconstruction results from the NaI detector
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Transcript of Preliminary pinhole SPECT reconstruction results from the NaI detector
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Preliminary pinhole SPECT reconstruction results from the NaI detectorImages are displayed as MIP (maximum-intensity-re-projections) animations
Please use slide show mode to see the animation
Reconstruction cineProjection cine
Fig.25 Misure al Johns Hopkins, Giugno 2006. Topo con MDP (si fissa nelle ossa)
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Preliminary pinhole SPECT reconstruction results from the CsI detectorImages are displayed as MIP (maximum-intensity-re-projections) animations
2 point sources APOE mouse (kidneys shown)
Flood imageSample projectio
nimage
Fig. 28 APOE mice
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APPROACH
Transgenic mouse modelAPOE-/- miceSpontaneous growth of atherosclerotic plaques accelerated by fatty diet
Imaging agent99mTc-HYNIC-Annexin-V Binds to apoptotic cells
Imaging techniquesHigh-resolution pinhole SPECT
ApomateTM: Trade name for Hynic Annexin V, North
American Scientific, Inc.
20 weeks
Plaque?
ApoE-/- mice
99mTc-Annexin-V SPECT images
Excised aorta from 37 weeks mouse
Photo autoradiography
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0.9 mm 99mTc capillars, 1.3 mm step
1.3 mm
FWHM1.05 mm
1.1 capillars, 1.5 mm step
0.9 capillars, 1.3 mm step
Spatial resolution: 0.55 mm !!
0.38 mm W pinhole, M=3.3, CsI:Tl array 1 mm step
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Other simulations done for the CsI(Na) option evaluation….
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CsI(Na) is an interesting option. Unfortunately arrays with pixels smaller than 0.8 mm pitch cannot be built. It is igroscopic, so a window is needed (with spatial resolution degradation) or the integral line layout has to be used.
Careful evaluation of the different options has to be done validating the simulations by measurements first.
Then, decision to be taken on the SNR evaluation base looking at the specific application
Tradeoff
spatial resolution/efficiency/
energy resolution
summarizing
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FOV
sensitivity
Rt
Scaling down (100 mm , 1 mm pitch ---> 50 mm 0.5 mm pitch)
Choosing the right M to get the best compromise between FOV, Rt and sensitivity
For example, to improve Rt, just sacrify FOV getting at the same time better sensitivity
Rt=0.1mm
FOV~5mm
Trading off…