AAA算法和PBC算法在鼻咽癌调强放疗中剂量分布的比较

Comparison of Dose Distribution of Anisotropic Analytical Algorithm (AAA) and Pencil Beam Convolution (PBC) Algorithm for Intensity Modulated Radiotherapy (IMRT) Treatment of Nasopharyngeal

目的:比较瓦里安Eclipse治疗计划系统中AAA算法和PBC算法在鼻咽癌调强放疗中靶区的剂量分布和危及器官受照剂量的差别。方法:选择我科治疗的鼻咽癌患者10例,分别采用Eclipse(7.6版本)治疗计划系统中AAA算法和PBC算法进行调强优化,优化条件相同,计算剂量分布。分析并比较10例患者的靶区、危及器官的受照剂量。结果:发现PBC算法和AAA算法对靶区剂量(PTV)影响不大,对脑干、晶体、视神经、脊髓四种危及器官的影响中,晶体的剂量差别较大,其次为视神经。结论:分析晶体受照剂量差别大的主要原因是晶体的受照剂量主要来自光栅运动中散射,AAA算法对散射的修正比PBC算法更为精确,所以在鼻咽癌调强治疗计划中AAA算法更为精确。

Objective： The aim of the study was to compare the dose distribution of PTV and OARs dose between IMRT plans for Nasopharyngeal using anisotropic analytical algorithm （AAA） and pencil beam convolution （PBC） methods in the Eclipse planning system （Varian Medical Systems）. Methods： For 10 patients with Nasopharyngeal, using Eclipse planning system to create treatment plans with AAA and PBC algorithms, and the setting conditions of these treatment plans were identical. Analyz- ing and comparing dose distribution of PTV and OARs dose for treatment plans of 10 patients. Results：There was no signifi- cant difference in the doses of the PTV;For the dose of OARs, the dose difference of Len was largest compared with Brain stem, Optic nerve, Spinal. Conclusions：The main dose of Len was caused by the scatter. Comparing with the PBC algorithm, AAA al- gorithm has shown good accuracy for scatter dose calculating, so AAA algorithm is more accurate for Nasopharyngeal