| 摘要 |
A flying spot X-ray scanning system includes a grid controlled X-ray tube and associated collimators for producing a pencil beam of X-rays which is adapted to repeatedly scan along a line through a body to be examined and across an associated detector. The grid of the X-ray tube is energized by a train of rectangularly shaped pulses, and separate control means are provided for selectively varying the commencement of each such pulse thereby to determine the position of the scan field relative to the body being examined, and for selectively varying the duration of each pulse thereby to control the width of the scan field. The X-ray tube, collimators, and detector are adapted to be moved as a unit in a direction transverse to the scan line of the pencil beam, and a further control is provided for selectively varying the extent of this transverse movement thereby to control the longitudinal dimension of the scan field.
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