碳离子束射程快速验证方法的蒙特卡罗模拟研究

可通过楔形装置把离子束(质子和重离子)纵向上的的深度剂量分布转换成横向上的剂量分布，进行离子束射程的快速测量及验证。本工作通过基于GEANT4内核的GATE蒙特卡罗模拟平台，模拟计算了不同能量碳离子束在用于制作楔形装置的铜、铝、铁和有机玻璃等材料中的深度剂量分布，得到不同能量碳离子束在不同材料中Bragg峰位所处深度与能量之间的关系；模拟计算了不同能量碳离子束穿越单楔板、双楔板和大小组合楔板等楔形装置后横向上的剂量分布，得到了横向剂量峰值出现位置与碳离子束射程之间的关系。本文蒙特卡罗模拟研究为进一步开发重离子治疗当中的射程快速验证方法与设备奠定了坚实的基础。

Monte Carlo Study on the Method of Rapid Range Verification of Carbon Ion Beam

The depth dose distribution of an ion beam (protons and heavy ions) in the longitudinal direction can be converted into a lateral dose profile via wedge devices for rapid measurement and verification on the range of the ion beam. In this work, the GEANT4 kernel-based GATE Monte Carlo simulation platform was used to calculate the depth dose distributions of various energy carbon-ion beams in materials of copper (Cu), aluminum (Al), iron (Fe) and polymethyl methacrylate (PMMA), which are usually applied to make wedge devices. The relationships between the beam energy and corresponding penetration depth of the Bragg peak position for the carbon ion beams in the various materials were obtained. The lateral dose profiles of carbon ion beams with different energies passing through a single wedge plate, a double wedge plate, and a large and small combined wedge plate were simulated and calculated under different configurations. Therefore, the relationships between the position of the peak of lateral dose and the beam range for the various energy carbon ion beams were acquired. Thus, our Monte Carlo simulations provided a substantial basis for further development of rapid range verification methods and devices in heavy ion therapy.