Radiological Image Enhancement by X-Ray Choppers

A new scatter control technology consisting a pair of X-ray choppers is being developed to provide improved radiographic contrast and measure geometrical distribution of scattered photons. By placing the choppers (which are rotating by different angular velocities) in two sides of the static object in direction of X-rays, the beam is position-encoded by two frequencies f1 and f2 due to the chopping velocities. The chopped beams reaching to image detectors generate a dynamic image consisting blinking pixels, while some non-chopped beams provide constant gray level of pixels. By extracting the gray value varying with compound frequency f1+f2 or f1-f2, the correct pathways of the beam are really selected, which have no scatter; whilst other provided frequencies including zero, f1, and f2 are due to scattered radiations. Hence, after video capturing by a digital fluoroscopy and digital image processing, an image is obtained which has better contrast in a region under both choppers. Using an assembled prototype device for a constructed phantom showed significantly image improvement.