Method and apparatus producing plural images of different contrast range

Abstract

A plurality of radiographic images of a subject are obtained simultaneously by situating the subject between a scanning X-ray source and an X-ray detector. The source has an electron beam which is swept through a raster pattern on a broad target to produce a moving X-ray origin point while the detector has an effective radiation-sensitive area which is very small in relation to the raster pattern. The X-axis and Y-axis beam deflection signals which control the X-ray source are also transmitted to both sets of raster signal terminals of a dual-image oscilloscope of the form having two deflectable electron beams for producing two separate images at a display screen. Both intensity signal terminals of the oscilloscope receive processed X-ray count signals from the detector through separate signal channels so that a pair of radiographic images of the scanned region of the subject are generated at the display screen. Separate signal processing circuits in each channel may be adjusted to have different gain factors and to establish different base levels and peak levels for the intensity signals enabling each radiographic image to emphasize a different aspect of the scanned region of the subject as each image may have a different contrast range. The plural images taken in conjunction exhibit contrast ranges which may exceed the contrast limitations of a single oscilloscope image or the similar limitations of photographic film which may be used to record the oscilloscope display.