Abstract

Info

Title:: Accuracy of dose calculation with CBCT images in patients with esophageal cancer

Author(s):: GONG Hanshun1; XU Shouping1; LIU Bo2; CAI Boning1; CONG Xiaohu1; CHEN Gaoxiang1; CUI Zeping1; 1. Department of Radiotherapy, Chinese PLA General Hospital, Beijing 100853, China; 2. College of Astronautics, Beihang University, Beijing 100083, China

Keywords:: ; Keywords: esophageal cancer; cone beam CT; HU value; dose calculation

Abstract:: Abstract: Objective To analyze the feasibility of using cone beam (CBCT) images for dose calculation in patients with esophageal cancer. Methods Eight patients receiving rotational intensity-modulated radiotherapy for esophageal cancer were enrolled in this study. Self-developed ART software was used to achieve accurate deformation registration and plan mapping of kVCT and the first fractional CBCT, and meanwhile histogram matching method was used to modify the HU values of CBCT. The obtained CBCT plans were imported into the original system. Finally, the HU-ED curve of kVCT was combined with monitor units for dose recalculation. Results The absolute deviations of dose and volume parameters of tissues in CBCT images from those in KCT images were less than 1%. According to the standard of 2 mm/2%/TH: 10%, the average gamma passing rate of each tissue received in the CBCT image relative to kVCT was over 99%. According to the standard of 1 mm/1%/TH: 10%, the mean gamma passing rates of target areas decreased significantly, with the lowest being 82.59%±16.16%, and the gamma passing rates of organs-at-risk were still above 98%. Conclusion The results fully verified the accuracy of dose calculation with CBCT image, and laid a certain foundation for direct dose calculation with CBCT images in adaptive radiotherapy.