Prim. filter for radiology - where geometric profile of filter can be modulated by remote control to alter contrast of image on viewing screen

摘要

A patient or a mechanical workpiece is located between a radiation source and a receiver which includes data- and image- processors. The source is provided with a prim. filter with a geometric shape which can be modulated by motors operated by remote control. The pref. filter consists of a rectangular frame contg. two gps. of filter blades. Each gp. of blades is located on a flexible cable which is spring-loaded; and each gp. can be moved by a row of rods which worms are fixed. The worms are rotated by electric motors fed by a controller. The result is that the blades form a hole of adjustable size and shape in the filter. Used for equalising the contrast in radiological images, e.g. in the radiography of a cardiac region masked by lungs with reduced density.