个体化调强适形放疗计划剂量验证方法的建立

A patient-specific quality assurance program for the dose delivery of intensity modulated radiotherapy

目的建立个体化调强适形放射治疗（IMRT）计划剂量验证的标准方法，探索调强剂量质量保证实施规范。方法选取2005年间在本院治疗的鼻咽癌患者33例，在三维计划系统上进行计划设计，然后将治疗计划移至固体体模上，得到体模杂交计划。利用电离室和胶片剂量仪对杂交计划的计算剂量同时进行测量验证，根据预设的误差控制标准对结果进行分析评估。结果所有患者的调强计划验证结果中有32例等中心点剂量误差在5％内符合，1例超出标准则重新选取两处剂量变化较缓区域补测点剂量，结果亦在5％内符合；相对剂量的验证以5％剂量偏差和3mm距离偏差为控制标准。所有病例均能满足。结论建立个体化剂量验证的标准方法是准确执行调强放疗计划的重要保证。

Objective To establish a standard program of the dose delivery for every individual patient andto study the criterion of quality assurance in intensity modulated radiotherapy （IMRT）. Methods 33 nasopharynx cancer （NPC） IMRT treatment plan were designed, then transferred to the hybrid plan in a 3D treatment plan system （CMS Xio）. The reference data were obtained. A ion chamber and Kodak EDR2 films were used to measure the absolute dose and the relative dose distribution, and difference between the reference value and measure value were evaluated with an advance criterion. Results For 32 cases, the absolute dose value at the isocenter was below the tolerance limit of 5 % ; for one case, the dose value exceeded the range, but re-meet the demand through adjusting the measure point to a flat region of dose distribution. For relative dose distribution, all cases meet the tolerance limit of 5 % and 3 mm distance difference. Conclusions To establish a standard program for individual patient is very important for the exact implement of IMRT plan.