Table III. Summary of PTV, organs at risk, and monitor units in the anatomical and functional plans (mean±standard deviation).

Homogeneity index was significantly increased in the functional plans compared to that in the anatomical plans (p=0.002). In contrast, no significant difference was seen in the conformity index among the two plans. In comparison with that in the anatomical plans, a significant reduction in the V_40Gy of the heart was observed in the functional plans (p=0.007). Significant differences were not observed in the maximum doses to the spinal cord or the mean doses to the esophagus. Compared to the anatomical plans, the functional plans showed a significant reduction in monitor units (p=0.050). PTV: Planning target volume; V_40Gy: the percentage volume of the heart receiving irradiation doses ≥40 Gy.