Performance evaluation of small field of view gamma camera

We have evaluated the performance characteristics of a small field of view (SFOV) gamma camera, a JanuCam made by Nucare Medical Systems, Inc., dedicated for a small organ such as breast, thyroid and joints. The gamma camera contains 2 inch PMTs coupled with a single slab of NaI(Tl) plate crystal. The characteristic performance is assessed following the standardized procedure outlined by the National Electrical Manufacturing Association (NEMA) NU 1-2007. The SFOV gamma camera provides an energy resolution of 9.86% for the Tc-99m source. The intrinsic spatial resolution is 3.21 mm for both the useful field of view (UFOV) and central field of view (CFOV). The differential spatial linearity is 0.16 mm (CFOV) and 0.17 mm (UFOV). The absolute spatial linearity is 0.19 mm (CFOV) and 0.22 mm (UFOV). The integral and differential uniformity for both CFOV and UFOV is greater than 1.23%. The extrinsic system sensitivity without scatter is 5,405 cpm/MBq (200 cpm/uCi) and is achieved by using a low energy general purpose (LEGP) collimator. The system spatial resolution acquired with LEGP is 6.2 mm full width at half maximum (FWHM) and 11.3 mm full width at tenth maximum (FWTM). The SFOV gamma camera provides high resolution with good uniformity which leads optimized performance for small organs.