Attenuator plate for use with X-ray apparatus.

摘要

A plate (10, 12) for insertion between a source of X-rays (16) and a patient (19) under examination has an X-ray transmission factor which varies across the surface of the plate in at least one of two orthogonal directions to provide a large number of alternate local maxima and minima of the transmission factor. The X-ray transmission factor at the minima are sufficiently greater than zero that primary X-rays are transmitted to a substantial extent through the entire area of the plate.