Preliminary pinhole SPECT reconstruction results from the NaI detector Images are displayed as MIP (maximum-intensity-re-projections) animations Please use slide show mode to see the animation Projection cine Reconstruction cine Fig.25 Misure al Johns Hopkins, Giugno 2006. Topo con MDP (si fissa nelle ossa)

Sample projection image Preliminary pinhole SPECT reconstruction results from the CsI detector Images are displayed as MIP (maximum-intensity-re-projections) animations 2 point sources APOE mouse (kidneys shown) Flood image Sample projection image Fig. 28 APOE mice

99mTc-Annexin-V SPECT images Excised aorta from 37 weeks mouse APPROACH Transgenic mouse model APOE-/- mice Spontaneous growth of atherosclerotic plaques accelerated by fatty diet Imaging agent 99mTc-HYNIC-Annexin-V Binds to apoptotic cells Imaging techniques High-resolution pinhole SPECT 99mTc-Annexin-V SPECT images Excised aorta from 37 weeks mouse Plaque? ApomateTM: Trade name for Hynic Annexin V, North American Scientific, Inc. ApoE-/- mice 20 weeks Photo autoradiography

Spatial resolution: 0.55 mm !! 0.38 mm W pinhole, M=3.3, CsI:Tl array 1 mm step 0.9 capillars, 1.3 mm step 1.1 capillars, 1.5 mm step 0.9 mm 99mTc capillars, 1.3 mm step Spatial resolution: 0.55 mm !! FWHM 1.05 mm 1.3 mm

Other simulations done for the CsI(Na) option evaluation….

spatial resolution/efficiency/ energy resolution summarizing 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

Scaling down (100 mm , 1 mm pitch ---> 50 mm 0.5 mm pitch) Rt Rt=0.1mm FOV FOV~5mm  sensitivity Trading off… 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