摘要
目的:检验调强适形放射治疗IntensitymodulatetradiationtherapyIMRT的剂量误差,探索IMRT的质量控制和质量保证的措施和方法。方法:1用体模治疗计划移植的方法对43例IMRT治疗计划的照射区以电离室作实际物理剂量测量,以验证治疗计划系统剂量计算的准确性,照射设备的可靠性和稳定性,修正IMRT治疗剂量误差和确定其剂量精度范围。2选取计划照射区内剂量梯度变化较大处进行重复摆位测量剂量,推算和验证由于摆位误差可能造成的剂量误差。结果:1与计划剂量比较,实际测量剂量的相对误差范围为-0.74%～4.98%并近似正态分布,平均误差为2.38%,标准差为1.39%,标准误为0.21%。全部43例的剂量误差均在5%以内。2实际测量的剂量梯度变化与计划剂量梯度一致。全部计划中的最大梯度值为15%/mm。在该处重复摆位测量的最大与最小值的相对差别为1.97%。结论:用体模计划移植测量方法能有效检验IMRT计划计算和执行的误差,可作为每个病人治疗前的剂量验证常规方法;IMRT治疗精度的保证需要优于1mm的额外精确摆位。
Objectives：To verify the dose accuracy a nd explo re for effective quality assurance（QA）procedure and measures of Peaco ck MIMic IMRT．Methods ：（１）Conducting hybrid plans using phant om geometry a nd ４３cases patient ' s incident beam fluence for peacock MIMic IMRT，with １０ ５°～２５５°arc，beaml et changed every ５°for each case．Irradiation dose we re measure d by ionization chamber to verify the dose calculation of the inverse plan ning and the reliability of total dose output of I MRT devices．（２）Dose distribution was measured repeatedly where the gradient was largest in the plan for testing the effect of positioning incorrectness．Results：（１）Relative di fference between measur ed dose and planned dose are within －０．７４％～４．９ ８％for all ４３cases，average di fference was ２．３８％，standard deviation wa s １．３９％and standard error was ０．２１％．（２）Measured dose gradient was consiste nt with planning．Maximum measured dose difference of repeat p ositioni ng at the most gradient poin t was １．９７％，where the gradient was １５mm per centimeter and largest in all ４３case s．Conclusion：Hybrid plan testing is ef ficient for dosi metry verification of IMRT planning and implementing．which sh ould be used as a QA procedure before e very patient ' s treatment．Additional p ositioning accuracy of less then １m m would be necessary when doing IMRT．
出处
《癌症》
SCIE
CAS
CSCD
北大核心
2001年第10期1092-1094,共3页
Chinese Journal of Cancer
基金
广东省鼻咽癌重点实验室基金项目(99-B-07703-S)
