| 摘要 |
A scanning and data acquisition method and apparatus for three-dimensional computerized tomographic imaging of a region of interest (ROI) of an object which is smaller than the object itself and having upper and lower boundaries which are completely within a field of view of an imaging system comprises merely a continuation of the scan trajectory used for scanning the main portion of the ROI so as to extend past its upper and lower boundaries. In a preferred embodiment, the scan path of the present invention consists of a main spiral scan path comprising a plurality of spiral turns, or stages, for scanning between upper and lower boundaries of the ROI, and at least a portion of an extra single spiral turn of the scan path at each end thereof. For image reconstruction, cone beam data for source positions corresponding to circular portions of the scan are approximated in the present invention by interpolation of data acquired from source positions on the extra spiral turn with data acquired from that turn of the main spiral scan that is adjacent thereto.
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