A hybrid processor for modifying and rearranging radionuclide scan data under direct observation.

Abstract

INTERPRETATION of radionuclide scan data is still a qualitative and descriptive procedure, but quantitative relationships of scan data are becoming more important. As a consequence, there is a trend of interest toward using automatic computation methods in this field. Since even the simplest scan picture is made up of an enormous amount of data, it is natural to apply the digital computer to these problems, for this instrument characteristically can store large amounts of data and process them rapidly according to instructions (3–5). The potential value of digital computation in scanning is just unfolding. Special emphasis has been given to improving picture quality by smoothing random fluctuations in count (4, 6–8), correcting for distortions in resolution (9, 10), subtracting one picture from another (4, 11), or adding counts representing selected structures in a picture or series of pictures for either statistical analysis or quantification of the time course of radiopharmaceutical in an organ (11–13). These applications are useful for specific practical problems in scanning, but their greatest significance now is in establishing and clarifying the basic principles of the method. The general requirements for a scan processor are that it permit nondestructive storage of the data and have provision for modifying and displaying these data subsequently in flexible ways so that they can be used more effectively. The generalpurpose digital computer, in its most common form, has special disadvantages when applied to image data; communication between computing equipment and the physician is inadequate, batch processing is restrictive, and the printed matrix of symbols is ineffective for visualization. This is a report of a hybrid system we developed to avoid these restrictions. It is a combination of digital processor (Figure 1, A) and analogue cathode-raytube (CRT) display (Figure 1, B), matched so that each is used to best advantage. Our processor for scan data is designed to provide for a wide and flexible range of data operations, direct picture display on a CRT screen in grey-shade and other picture formats, and full operator control of both processing and display operations at the time of viewing. The instrument does not require the user to learn complicated programming schemes. The operator is expected to be a physician who controls the parameters of interest by punching preset buttons on a keyboard while observing changes displayed on a CRT screen. The instrument is intended to serve as a central processor and reader for data from several scanning units. The System A. Drum Loading At the time of scanning, counts detected during each predetermined spatial interval of detector displacement are recorded in 6-bit binary code on standard 8-column perforated paper tape, along with position codes (TABLE I) (14).