Development of Support System for Aligning Dose-Distribution Images in Multiple Radiotherapy Using Nonlinear Registration Method.

In a repeated radiotherapy owing to a local recurrence close to the previous irradiation, the dose distribution of next irradiation is required to avoid overlap with previous one. Therefore, a system for displaying dose-distribution image of previous irradiation on a present anatomical image would be helpful in designing new radiotherapy. However, registration of two abdominal CT images acquired different period is difficult because of body movement and breathing. In this study, we developed a next generation system to support aligning the dosedistribution image of previous irradiation to the present radiation planning image using the 3-dimensional nonlinear registration method between previous and present X-ray abdominal CT images.