| 摘要 |
<p>An X-ray beam attenuator includes an attenuator plate (2) for location between an X-ray source (3) and an X-ray detector (5). The attenuator plate comprises a central window (12) of low beam attenuation and, radiating from the central window (12), a plurality of alternating segments of high and low X-ray attenuation (8, 14). During use, the attenuator plate (2) is rotated at speeds exceeding several hundred revolutions per minute. Beams passing through the central window provide a high quality, highly contrasting image, for imaging a region of interest, with the remaining incident beams providing an image of adequate quality and contrast. The invention reduces the exposure of a patient to X-rays, whilst not altering the characteristics of the X-ray beam. Thus, for example, image enhancement is rendered simple.</p> |
