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目的 探讨逆向调强适形放射治疗 (IMRT)过程中剂量学验证的方法 ,保证IMRT治疗计划临床实施的正确性。方法 针对实施IMRT病人 ,使用CMSFOCUS92 0 0三维治疗计划系统设计出 5野IMRT治疗计划。利用固体水模板在治疗计划系统中建立三维等效体模。将待验证病人的IMRT计划移置到体模中重新进行优化 ,计算出体模中感兴趣点或平面上的剂量和剂量分布。将体模移放到加速器治疗床上 ,调用体模IMRT计划数据对体模进行模拟照射。使用 0 2 3cc电离室测量出体模中感兴趣点上的吸收剂量 ;使用RIT 113胶片剂量分析系统测量出体模中感兴趣平面上的剂量分布。然后和计划系统计算的结果相比较 ,验证绝对剂量和相对剂量。结果 绝对剂量和相对剂量的测量结果基本上和计划系统计算的结果相一致。测量的绝对剂量误差在 3%以内 ,相对剂量曲线分布也是比较准确的。结论 IMRT计划剂量学验证是临床实施IMRT治疗过程中的可靠保证。
Objective To investigate the dosimetric verification of IMRT in order to ensure the correctness of IMRT treatment plan. Methods For the implementation of IMRT patients, a 5-field IMRT treatment plan was designed using the CMSFOCUS 9200 three-dimensional treatment planning system. The solid water template is used to establish a three-dimensional equivalent phantom in the treatment planning system. The IMRT plan of the patient to be validated is relocated to the phantom and re-optimized to calculate the dose and dose distribution at the point of interest or plane in the phantom. The phantom moved to the accelerator treatment bed, call the phantom IMRT plan data to simulate the phantom irradiation. The absorbed dose at the point of interest in the phantom was measured using a 0 2 3 cc ionization chamber; the dose distribution on the plane of interest in the phantom was measured using the RIT 113 Film Dose Analysis System. Then compared with the results calculated by the planning system, the absolute dose and the relative dose were validated. Results The absolute and relative dose measurements were basically consistent with those calculated by the planning system. The absolute dose error of measurement is within 3%, and the relative dose curve distribution is relatively accurate. Conclusion IMRT plan dosimetric verification is a reliable guarantee for the clinical implementation of IMRT.