| 摘要 |
PROBLEM TO BE SOLVED: To reduce the calculation time to determine the optimum irradiation condition on the basis of an operator-set condition concerning an irradiation direction, prescription dose, etc. through repeated calculation.SOLUTION: On the basis of the distances between the axes of beams emitted to spots and calculation points, dose matrices A, B which are the contributions from beams emitted to irradiation positions to doses to the calculation points are divided into matrices A, Bof doses which are to the calculation points falling within the target regions with the distance of the beam emitted to each spot from the beam axis being equal to or less than L and matrices A, Bof doses which are to the calculation points falling within the target regions with the distance from the beam axis being greater than L, and d, dcontaining the dose matrices A, Bare regarded as constants at the time of repeated calculation. In addition, when an update condition is satisfied, objective functions are recalculated and updated using the values of the spot irradiation amount xand dose matrices A, B calculated at the time. |
