Patent ID: 7340029

Claim:
An x-ray computed tomography apparatus comprising: a stationary x-ray generator having a target that at least partially surrounds an examination volume in a plane, said x-ray generator emitting an x-ray beam from a focus that moves around the examination volume on said target; a stationary x-ray detector that at least partially surrounds said examination volume, said stationary x-ray detector comprising a plurality of detector elements and said x-ray beam proceeding through said examination volume onto respective, momentarily opposite detector elements of said x-ray detector; a carrier frame carrying a Z-collimator that limits expansion of said x-ray beam in a direction along said system axis, said carrier frame being mounted to rotate around a system axis in synchronization with movement of said focus to maintain interaction between said at least one shaping element and said x-ray beam as said focus moves around said examination volume; and said Z-collimator comprising at least two parallel beam-limiting lamellae, between which said x-ray beam proceeds, said lamellae having respective edges each having a non-linear shape that, when projected onto the x-ray detector by the x-ray beam, produces a projected shape substantially coinciding with a side of said x-ray detector along said system axis.