Effects of position shift and dose adjustment on pass rate of IMRT dose verification / 医疗卫生装备

ABSTRACT

Objective To analyze the effects of position shift and dose adjustment on the pass rate of IMRT dose verification to facilitate to obtain rapidly high-pass-rate IMRT dose verification report.Methods At first,the dose unit of measuring dose map image and planning Dose Profile was unified.Secondly,the planning Dose Profile was moved at lateral and cephal-ocaudal directions respectively in contrast mode so as to determine the position error with the maximum pass rate.Thirdly,the highest pass rate point of dose verification was found in the range of dose adjustment.Fourthly,the plan report with the highest pass rate of dose verification was found out by adjusting position error and dose coefficient.Results The highest pass rate was obtained in case the displacement was-3 mm at lateral direction or +3 mm at cephal-ocaudal direction;high pass rate was got when dose adjustment coefficient was 1.02;high pass rate was achieved in case the displacement was-3 mm at lateral direction,+2 mm at cephal-ocaudal direction and the dose adjustment coefficient was 1.02,which was significantly different from those with other combined values (P＜0.05).Conclusion The dose verification technique is convenient and quick when used to obtain a high-pass-rate dose verification report.