Development of four-dimensional CT acquisition and tumor detection system during volumetric modulated arc therapy.

点击翻译按钮获取中文摘要

In this study, we have developed in-treatment kilo-voltage four-dimensional cone-beam CT (in-treatment kV 4D CBCT) acquisition during volumetric modulated arc therapy (VMAT) by use of the image-based phase recognition technique of projection images. With the in-treatment kV 4D CBCT, the respiratory motion of lung tumors has been quantitatively evaluated for the first time, and the margin applied in treatment planning has been retrospectively reanalyzed. In addition, the CBCT reconstruction using the portal images of VMAT beam and its four dimensional version (4D VMAT CBCT) have been developed. With the 4D VMAT CBCT, the tumor location and movement were visually observed. Combining 4D VMAT CBCT with in-treatment kV 4D CBCT, it is expected that the appropriate margin setting and the reduction of the extra-radiation dose for normal tissue are achieved.