利用二维电离室矩阵验证食管癌调强放疗的剂量分布

Verification of dose distribution in intensive modulation radiotherapy( IMRT) for esophageal cancer patients with 2D ionization chamber array

目的比较实际受照剂量分布与计划剂量分布,评价食管癌调强放射治疗计划处方实施的准确性。方法选取135例食管癌患者,采用束流调强放射治疗,并将其中99例治疗计划移植到二维电离室矩阵和验证模体中,生成验证计划,在加速器上进行模拟治疗。利用二维电离室矩阵进行测量,将测得剂量数据和计划剂量数据进行比较和分析。结果经过Gamma分析(按3%/3 mm的误差标准),82.8%的计划验证通过率≥90.0%,平均通过率为94.8%,标准误差为0.6%。结论实际测量剂量分布与计划剂量分布符合情况基本理想,部分治疗计划需进一步调试修正直至验证通过后才可用于临床治疗。

Objective To evaluate the accuracy of radiation dose plan in intensive modulation radiotherapy （IMRT） for patients with esophageal cancer. Methods One hundred and thirty five patients with esophageal cancer underwent IMRT. The close plans were designed and 99 dose plans were moved into 2D-An＇ay ionization chamber and phantom. Assurance plans were developed and treatment was simulated on linear accelerator. Radiation doses were measured with 2D-Array ionization chamber and compared to the plans. Results Gamma analysis at the 3%/3 mm criteria revealed that the pass rates of 82.8% plans were ≥90.0% with an average rate of 94.8% （ SE ： 0.6% ）. Conclusion The consistency of measured dose distribution with the planned dose distribution is satisfactory, but some treatment plans need to be tested and modified before clinical application.