Design features and performance of a CsI(Na) array based gamma camera for small animal gene research

The authors report on the development and performance of a radiation imaging system based on a 110 mm diameter matrix of 1 mm/spl times/1 mm size CsI(Na) scintillating crystals. This detector system has been optimized for high resolution radiation imaging of the distribution of iodine 125 (/sup 125/I) in a laboratory animal. The radioisotope /sup 125/I is readily available as a label to molecular biology probes that can be used in gene research. The system utilizes the Hamamatsu 5 inch diameter 3292 position sensitive photomultiplier tube (PSPMT) coupled to the CsI(Na) matrix and a custom built high resolution copper-beryllium collimator. A resulting spatial resolution of the order of 1.5 mm FWHM and a sensitivity of 68 cpm//spl mu/Ci were obtained with the copper-beryllium collimator. The detector system is installed on a rotating gantry to obtain multiple projections and is now being used in animal studies.