Data processing device for use in scintillation camera apparatus

Abstract

A scintillation camera apparatus adapted for displaying an image representing a radioisotope distribution within a subject under examination at a substantially constant level in image density during a persistent data acquisition procedure comprises an auxiliary memory for sequentially storing position signals representing detected positions of gamma rays, and an image memory for storing a count representing the frequency of detection of gamma rays in a memory location accessed by position signals. The auxiliary memory has a predetermined capacity, and thus, when the number of the sequentially stored position signals exceeds this memory capacity, the earliest-entered position signals stored therein are made to overflow therefrom. A memory controller accesses a location in the image memory by means of the overflowed position signals and decrements the content at the accessed location. After position signals are made to overflow from the auxiliary memory, the quantity of data stored in the image memory (the total number of counts of gamma rays) remains always at a constant value equal to the capacity of the auxiliary memory.