Compact high resolution detector for small animal SPECT

We present a high-resolution detector for small animal SPECT and the scinti graphic examination of human extremities or scintimammography. The system c onsists of a 2mm NaI(Tl) disk coupled to a 5 " position sensitive photomult iplier (Hamamatsu, R3292) and an ultra high-resolution, parallel-hole colli mator. The usable FOV of this detector has a diameter of 90mm. The intrinsi c spatial resolution is 1.4mm FWHM and the energy resolution at 140keV amou nts to 8.7%. The system resolution is 1.8mm FWHM close to the collimator an d 2.5mm at 30mm source distance with a system sensitivity of 8.8cps/MBq. Us ing an iterative reconstruction algorithm the tomographical resolution (in water) amounts to 2.7mm. When using a pinhole collimator (1.1mm aperture) t he system resolution at 30mm improves to 1.4mm and the sensitivity increase s by a factor of 3.2 to an absolute value of 27.9cps/MBq.