Design of compact pinhole SPECT system based on flat panel PMT

The present development of new gamma imagers has allowed to realize detectors with ultra high spatial resolution and very compact size for PET as well as for SPET application. In this paper we analyze and discuss the possible design of new pinhole SPECT scanners based on heads which consist of flat panel PSPMT and different design of scintillation arrays like NaI(Tl), 1 mm pixel size, and CsI(Tl) multi layers array, mounted in off centered configuration to improve the intrinsic spatial resolution of the imagers. The results show that an array configuration 2×2 Hamamatsu flat panel PSPMTs coupled to NaI(Tl) scintillation array with 1 mm pixel size, represents the best trade off between compactness and spatial resolution of pinhole SPET scanner. The use of off centered CsI(Tl) scintillation array coupled to a single flat panel PSPMT allows to arrange a high sensitivity and very compact pinhole SPET scanner at very low cost only worsening of 50% spatial resolution than an Anger gamma camera pinhole SPECT.