A radiographic system using on-line computer control of x-ray microbeam scan, which has been developed recently by the present authors, provides effective means for the selective exposures of the specified sample points on the object, and quantitative measurements of the transmitted x-ray intensities. The system also makes it possible to trace an outline of the object or to track a point on a moving organ.
Present paper describes an interactive display terminal of the scanned x-ray image, which has been developed for assisting the computer measurements through visual inspections of the x-ray image. For the preliminary observation of the object, a low exposure x-ray image by the x-ray microbeam scan is recorded using a scan converter tube and displayed on a TV-monitor. A cross mark is displayed, superposed upon the x-ray image, to specify the selected position on theobject. Location of the cross is controlled by manual switches and the coordinate values are read into the computer. Computer exposes sample points at selected position and records spatio-temporal variations of the x-ray intensities. It has been deaionstrated that the method is useful for the observations of the movements of organs including pulsating movements of the cardiac wall. Present system has also been applied successfully to the automatic tracing of a selected portion of the outline of the organ such as a barium meal full stomach.