Advances in nuclear medicine imaging instrumentation

In the four years since the previous IAEA Symposium significant developments have occurred in both commercial imaging instrumentation and new position sensitive detectors which show promise as the basis of new imaging instruments for use in nuclear medicine. The paper reviews the development of Anger cameras with emphasis on improvements of recent years. New detectors which would complement the Anger camera in certain applications within nuclear medicine are discussed in some detail. Recent developments in the Anger camera include more efficient optical coupling to the sodium iodide crystal yielding better spatial and energy resolution and generally better count-rate performance. A digital technique giving improved uniformity is discussed. A summary of current specifications of Anger cameras is included. A commercial matrix scintillation detector with integral computer and high-speed electronics is reviewed in relationship to the Anger camera and specifications are presented. New detectors are compared with the Anger camera and evaluated. These detectors include image intensifiers, multiwire proportional cameras and semiconductor detectors. The basic principles of each of these detectors are discussed and evaluated. The use of coded apertures as a means of eliminating the collimator is evaluated and compared with existing methods. A discussion of the necessary specifications for detectors to be used with coded apertures is presented. (author)