调强放疗小野小跳数TPS计算值与实际测量值间差异的研究

Study of difference between calculation of TPS and measure of small segment and small monitor unit in IMRT

目的对调强放疗中的小野和小跳数在TPS计算与加速器实际测量值之间的差异进行研究,以指导调强放疗技术在临床中的应用。方法在TPS中设计小野和小跳数计划并导出,与在加速器上进行的实际测量结果进行比较。结果在小跳数测量中,2MU以上的通过率均>83%;在小野测量中,面积大于2 cm×2 cm的射野通过率均>80%。结论对TPS计算的小野和小跳数需进行手动适当调整;MLC的到位精度对小野的影响比较大,MLC的质量控制不容忽视。

Objective To study the difference between the calculation of TPS and the measurement of small segment and small moni-tor unit in IMRT to instruct the clinical application.Methods The small segment and small monitor unit plan were created and exported in TPS,and compared with the results of measurement in LA.Results In small MU testing the passing rate of over 2MU was more than 83%;in small segment testing the passing rate of the area over 2cm ×2 cm was more than 80%.Conclusion Manual operation should be per-formed in the mall segment and small monitor unit calculated in TPS.MLC leaf positional accuracy is important for the small field,so QA/QC for MLC can not be ignored.