PROBLEM TO BE SOLVED: To provide an X-ray irradiation field control method in a collimator mechanism, capable of accurately and quickly adjusting an X-ray irradiation field.SOLUTION: The X-ray irradiation field control method includes: an error measuring process of obtaining two or more pieces of error data indicating relation between the command value of a movement amount and the error of the X-ray irradiation field a first relational expression preparing process of preparing a first relational expression indicating the relation between the command value of the movement amount and the error of the X-ray irradiation field by Taylor-expanding the two or more pieces of error data a process of obtaining two or more pieces of coefficient data indicating the relation between a distance, between radiation source received images, and a coefficient in the first relational expression by changing the distance, between the radiation source received images, and repeating the error measuring process and the first relational expression preparing process for two or more times a process of preparing a second relational expression indicating the relation between the distance, between the radiation source received images, and the coefficient in the first relational expression at the time by Taylor-expanding the two or more pieces of coefficient data and a process of computing the movement amount of a moving member from the distance, between the radiation source received images, the first relational expression and the second relational expression.COPYRIGHT: (C)2012,JPO&INPIT【課題】 X線照射野を正確かつ迅速に調整することが可能なコリメータ機構におけるX線照射野制御方法を提供する。【解決手段】 移動量の指令値とX線照射野の誤差との関係を示す複数の誤差データを得る誤差測定工程と、これら複数の誤差データをテイラー展開することにより移動量の指令値とX線照射野の誤差との関係を示す第1関係式を作成する第1関係式作成工程と、誤差測定工程と第1関係式作成工程とを線源受像画間距離を変更して複数回繰り返して線源受像画間距離と第1関係式における係数との関係を示す複数の係数データを得る工程と、これら複数の係数データをテイラー展開することにより線源受像画間距離とそのときの第1関係式における係数との関係を示す第2関係式を作成する工程と、線源受像画間距離と第1関係式および第2関係式とから移動部材の移動量を演算する工程とを備える。【選択図】 図5
