| 摘要 |
In an X-ray examination apparatus comprising an image intensifier tube and an optical light distribution system there is included an image field selector, by means of which, using a subbeam diverted from the imaging beam, a measurement field can be selected and by means of which this measurement field or a boundary outline thereof can be projected back into the imaging radiation path. Thus, it is achieved that during an examination stage an indication of the extent and location of a measurement field which is considered to be relevant for controlling the desired exposure for pictures to be produced, can be constantly displayed on the image screen of the television monitor.
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