| 摘要 |
In an illustrated embodiment a plurality of x-ray sources are arranged at equal angles about a rotating frame. Each source and detector arrangement may provide the desired number of measurements such as 240, so that the required angular movement for scanning is reduced by a factor corresponding to the number of sources. In one embodiment with three sources and 240 detectors for each source, the desired number of measured values may be obtained by rotation through 120 degrees instead of 360 degrees. In another illustrative embodiment, the narrow beam from the x-ray source covers about 30 detectors, the beam and detectors being linearly scanned so as to generate about 240 measurements, there being three source-detector arrangements separated by 60 degrees, so that scanning is carried out by rotation through 60 degrees rather than 180 degrees.
|
