| 摘要 |
PROBLEM TO BE SOLVED: To facilitate to reduce X-ray exposure to a patient when helically scanning with a computer-type tomographic system (10). SOLUTION: The present invention provides a method, an apparatus and a system to control X-ray irradiation during scanning with the computer-type tomographic system (10). The computer-type tomographic system comprises an X-ray source (14), a collimator (52) and a detector array (18). The collimator includes a first cam (81) which is structured so as to adjust a shutter of the x-ray fan beam (16) generated from the X-ray source in a first direction, a second cam (82) which is located at the opposite side of the first cam with regard to the focal point (50) of the X-ray source and structured so as to adjust a shutter of the X-ray fan beam in a second direction, opposite to the first direction, and the cam driving device which is structured so as to dispose at least either the first cam or the second cam during scanning. COPYRIGHT: (C)2006,JPO&NCIPI
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