| 摘要 |
<p>A contour is determined in the X-ray image by means of an image processing unit (13) in an X-ray examination apparatus (2,5) so that arithmetic means (16) can determine the position of absorbing diaphragm slats (24,25;26,27) which enclose a minimum area situated around the contour. The diaphragm slats are moved to the correct position by way of a drive unit (17). As a result, overexposure of the X-ray image intensifier tube (5) is counteracted and the medical details in the image become more distinct. Image harmonization can be realised by using X-ray absorbing wedges (43-46), arrangement of the wedges in excessively light parts of the X-ray image enables the dynamic range to be increased at areas of interest. The position of the wedges is calculated on the basis of a dose calculation based on an exposure time and the voltage and current applied to the X-ray source (2), said quantities being applied to the arithmetic means via a control unit (15). <IMAGE></p> |
