An Improved Convolution Algorithm of Cylinder String Based on Unified Coordinate System

Tube string convolution algorithm is a commonly used dose verification algorithm in radiotherapy. It has the advantages of fast operation time, high verification accuracy, and no need for specific structural parameters of the accelerator head for modeling. However, it is often necessary to establish a ray coordinate system for each ray and divide the cylinder string area in the ray coordinate system, which makes the algorithm involve multi coordinate system conversion and other issues. In this paper, a CCC algorithm in a unified coordinate system is proposed to solve this problem. On the premise of not affecting the verification accuracy, the affected points and their outer point coordinates are used to divide the cylinder string area, avoiding the problem of coordinate conversion in multiple coordinate systems, and simplifying the algorithm modeling process.