Radiography apparatus wherein interleaving of beam paths is effected by changing the phase of the timing pulses

Claim 1

Radiographic apparatus comprising a source of a substantially planar spread of penetrating radiation, means for supporting said source to project said radiation across an opening in which a body to be examined can be inserted, the spread of radiation being disposed to irradiate a selected cross-sectional slice of said body, means for angularly moving said means for supporting, and with it said source, about an axis intersecting said slice, a plurality of detector devices disposed to receive radiation directed through said slice along a plurality of groups of divergent beam paths, in said slice, during said angular movement, a signal channel for each detector device arranged to receive output signals, developed by said detector devices and indicative of the absorption suffered by said radiation on traversing said beam paths, and means for generating timing signals for application to said channels to distinguish the output signals relating to each of said groups, said timing signals being related to the angular movement of said means for supporting relative to said body, and means, effective during said angular movement for changing the relationship between said timing signals and said angular movement, so as to derive output signals relating to more of said groups of beam paths than would have been available without said change of relationship.