| 摘要 |
1475492 Radiography EMI Ltd 20 May 1974 [1 June 1973] 26325/73 Heading H4F In an apparatus for examining a body held at 1 with a planar swath 7 of X-rays from a source 2, the source and an array of detectors 8 are rotated on an annulus 3 about the object and the outputs from the detectors 8 are used to provide a representation of the object in a circuit 11, the outputs of the detectors 8 being modified in response to the outputs of detectors 12 which monitor the transverse uniformity of the incident swath 7 at a collimator 6 and feed correction signals via circuit 13 for combination at 10 with the uncorrected image signals. The source of X-rays is preferably a rotating anode Coolidge tube. An absorbing wedge can be placed across the swath to provide uniform hardness of the rays. Variations in radiation resulting from rotation of the anode can be compensated by having a phosphor spot on the anode arranged to cross the electron beam once on each rotation and using the light signal so produced to provide further correction of the output signals.
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