| 摘要 |
<p>A computed tomography method and apparatus for sequentially projecting partial fan beams through a sample (32), measuring data resulting from each projection, and generating an image of a sample section from the measured data without reordering the measured data to simulate data obtained by projecting parallel ray beams through the sample (32). Partial fan beam radiation received at a detector array (44) is processed to image a larger diameter sample section than could be imaged with full fan beams projected from the same source to the same detector array (44) with the same source-to-detector spacing(s). Preferably, X-ray radiation is transmitted through the sample (32) and the system includes an image intensifier tube (40) for receiving data representing at least a portion of the transmitted radiation. Preferably, the invention includes a linear detector array (44) which receives the image intensifier tube output and an extension detector array (45) which receives partial fan beam radiation which has propagated through the sample but which is not incident at the image intensifier tube. The data measured during each partial fan beam scan are preferably weighted to simulate full fan beam data. The weighted partial fan data signals are then processed in the same way as if they were unweighted data signals resulting from exposure of the sample (32) to full fan beams.</p> |
