A low-energy multihole converging collimator compared with a pinhole collimator.

Abstract

It is apparent from the equations describing the performance of the pinhole and converging collimators on the scintillation camera that the sensitivity, resolution, and field of view of these two collimators are very different as a function of distance from the collimator face. A 6000-hole converging collimator designed for /sup 99m/Tc havin a 15-cm field of view diameter at 10 cm from the collimator face was constructed and compared with the Searle Radiographicas pinhole collimator. The sensitivity of the converging collimator increases with depth while that of the pinhole collimator decreases. The resolution of the collimator-camera system degrades more rapidly with depth fur the pinhole collamator. The field of view of the converging collimator decreases with increasing object-tocollimator distances while that of the pinhole collimator increase with depth. The experimental results agree with the derived equations and imply that the converging collimator has very different performance characteristics from the pinhole collimator and that it should be useful in the imaging of small organs. (auth)