Evaluation of hand-held gamma camera with 1-mm NaI(Tl) pixels

A high resolution, hand-held gamma camera has been constructed for use in pre-surgical and intra-operative lymphoscintigraphy. In this paper, we evaluate a compact gamma camera system utilizing NaI(Tl) as a more likely candidate for scintillator due to its greater light yield and faster decay time than CsI(Na) used in an earlier prototype. Using NaI(Tl), the system mean energy resolution is 13% FWHM at 122keV, as compared to 28% in the system with CsI(Na). The highly compact detector head has a 2-cm by 2-cm field of view (FOV) and 1.25-mm intrinsic spatial resolution. Sensitivity of the NaI(Tl) camera was compared with the CsI(Na) camera. At 1cm distance from the tip of collimator, pinhole sensitivity was 58 cps/μCi for the Na(Tl) camera and 37 cps/μCi for the CsI(Na) camera.