| 摘要 |
<P>PROBLEM TO BE SOLVED: To attain faster processing by reducing the number of copies of DRR creation and reducing the calculation cost in the whole processing. <P>SOLUTION: In automatic positioning for a patient in radiotherapy devised to calculate the amount of out of alignment between a current position of the patient and a position in treatment planning in which, in registering three-dimensional CT image data, acquired in the treatment planning, and a two-dimensional X ray perspective image to be acquired in the positioning, in order to align the positions of the three-dimensional CT image data with the two-dimensional X-ray perspective image, the geometry of the X ray photography is reproduced on a computer, by virtually executing perspective projection to the CT image data, the two-dimensional DRR is obtained, so that a valuation function for evaluating the degree of coincidence of the DRR and the X ray perspective image is maximum, the perspective projection parameter regarding rotation and parallel translation of the CT image data is optimized, optimization for the perspective projection parameter is executed by calculating the evaluation value for the degree of the coincidence of the DRR and the real perspective image only in one direction where a change in the image is greater. <P>COPYRIGHT: (C)2013,JPO&INPIT |
