摘要
针对容积旋转调强放疗计划系统的剂量精度验证问题,考察剂量计算中照射弧的离散化处理对剂量验证的影响。通过改变模拟射野随机架角的变化关系并结合γ因子分析,结果表明:当射野形状随机架角变化缓慢时,增大离散间隔,主要对低剂量区的剂量分布有明显影响,90%剂量检验通过率容易达到;当射野形状随机架角变化快时,增大离散间隔对低剂量和高剂量区的剂量分布都有明显影响,剂量检验通过率明显降低,此时照射弧的离散化角度间隔应不大于4°,才能获得较满意的剂量检验通过率。另外,剂量检验通过率与模体几何和旋转调强的等中心位置的选取没有明显的依赖性。
The influence of discretization treatment of irradiation arc in the dose calculation is inspected in allusion to the problem on verification of dose precision in the radiation treatment planning system of volumetric modulated arc therapy（VMAT）. By changing the variable relationship of simulated field along with the gantry angle and combining with factor analysis, it discovers that when the variation of the field shape is moderate, the discretization clearance is enlarged,which has obvious influence on low-dosage area mainly,and passing rate of dose verification is easy to reach 90%. When the variation of the field shape is fast along with the gantry angle,enlargement of discretization clearance has obvious influence on both the low-dose and high-dose areas, and passing rate of dose verification is reduced obviously. Under such circumstances,discretization angle clearance of irradiation arc shall not be greater than 4°, and then satisfied passing rate of dose verification can be acquired. In addition, passing rate of dose verification weakly depends on the phantom geometry and the VMAT isocenter location.
出处
《中国测试》
CAS
北大核心
2016年第6期23-28,共6页
China Measurement & Test
