Recent results of a high-resolution animal SPECT

Summary form only received as follows: The authors present the prototype of a compact, high-resolution animal SPECT. The detector of this system consists of a 3 mm NaI(Tl) disk coupled to a 5" position sensitive photomultiplier (Hamamatsu, R3292). It can be equipped with either high-resolution parallel-hole collimators or a pinhole collimator with exchangeable tungsten aperture. The usable FOV of the detector has a diameter of 85 mm, the intrinsic spatial resolution is 2.0 mm FWHM and the energy resolution at 140 keV amounts to 9.6%. For a LEUHR parallel-hole collimator the authors find a system resolution of 2.7 mm FWHM at 30 mm source distance and a system sensitivity of 22.3 cps/MBq. Using an iterative reconstruction algorithm a tomographical resolution (in water) of 2.8 mm is measured. With the pinhole collimator (1.1 mm aperture) the system resolution improves to less than 1.5 mm and the sensitivity increases by a factor of 1.8.