Abstract
This study reports on the geometric weighting factor (k) for the collimator exchange effect in a rectangular irradiation field. We examined SeqD and Sc using a regression analysis, about k when we used a report type of Kim,4) and when we used the least squares method and the bisection method. The distribution of k in the bisection method approximated the standard normal distribution of the type that concentrated at the center, and it was shown that the theory of k was appropriate. The values of k were 1.779, 2.233, and 2.478 in each method. The coefficient of determination adjusted by the degree of freedom (R*2) in SeqD was 0.978, 0.990, and 0.992 each. In k=1.779 and k=2.478, it was p=0.05. Therefore, a significant difference was recognized. R*2 in Sc was 0.987, 0.993, and 0.991 each, and the significant difference was not recognized. It is thought that k calculation by the dichotomy is effective in confirming the accuracy of the measurement value when Sc is calculated. The values for k in the bisection method of X<Y and X>Y was 2.514 and 2.443 each. R*2 was 0.985 and 0.996 in SeqD and 0.984 and 0.998 in Sc. The difference between SeqD and Sc was significant (p=0.018, p<0.001). Cancellation of the error margin factor in X<Y will be considered for future tasks in the Sc calculation using k.
