多通道剂量测量仪在调强放疗剂量检测中的应用

Absolute Dose Verification of Intensity Modulated Radiation Therapy with Multi-channel Dose Measure Iinstrument

目的:保证调强放疗治疗计划临床实施的正确性。方法:分别用0 cGy、50 cGy、100 cGy、150 cGy、200 cGy、250 cGy、300 cGy照射多通道剂量仪金属氧化物半导体场效应晶体管(MOSFET)探头,观察多通道剂量仪读数;大机架分别旋转0、30、60、90、120、150、180、210、240、270、300度时,计划照射探头100 cGy时,观察多通道剂量仪读数;采用多通道剂量仪验证空间多点绝对剂量。结果:计划剂量与多通道剂量仪探头阈值电压之间呈正相关关系(r=1,P=0.0000);计划剂量与多通道剂量仪探头读数剂量之间呈正相关关系,(r=1,P=0.0000);测得多通道剂量仪MOSFET探头,轴方向性误差<2%;在模体中测量绝对剂量,等中心点实测剂量与计划剂量误差在3%以内,其它偏离点的实测剂量与计划剂量误差在5%以内。结论:应用多通道剂量仪测量IMRT绝对剂量是可行的,可有效地保证IMRT的顺利开展。

Objective： To ensure the accuracy of intensity modulated radiation therapy. Methods： The MOSFET probe of mul- ti-channel dose measure instrument was radiated by 0 cGy, 50 cGy, 100 cGy, 150 cGy, 200 cGy, 250 eGy and 300 cGy, abso- lute dose was measured with multi-channel dose measure instrument, the MOSFET was radiated by 100 cGy where the gantry was on 0, 30, 60, 90, 120, 150, 180, 210, 240, 270 and 300 angle, absolute dose was measured with the multi-channel dose mea- sure ins^ment, Results： The threshold voltage of MOSFET and the plan dose was positive correlation （r=l, P=-0.0000）, the plan dose and indication dose of the multi-channel dose measure instrument was positive correlation （r=l, P=-0.0000）, the toler- ance measured with the multi-channel dose measure instrument was less than 2% where the gantry on different angle. The errors between the indication dose and plan dose in the central point were less than 3%, whereas the errors in another eccentric point were less than 5%. Conclusions： Absolute dose of IMRT may be measured with the multi-channel dose measure instrument and ensure quality of IMRT.