电子束全身皮肤照射剂量测定和分析

目的 对电子束全身皮肤照射进行剂量学参数的测量。方法 在Varian23EX加速器上采用双机架六野照射技术,使用平行板电离室、胶片、热释光元件等对源皮距400cm处6MeV电子束的剂量学参数进行测量。结果 治疗平面的剂量场均匀性到达±5%。单照射野体表剂量80%以上,最大深度0.6cm,80%和50%剂量深度分别为1.10cm和1.42cm。双机架六野最大剂量深度接近皮肤表面,80%和50%剂量深度分别为0.40cm和1.00cm处。X射线污染为2.2%。累积因子平均值3.05。结论 全身电子束照射条件下电子束剂量特性与常规条件下特性有很大不同,必须通过实际测量来为临床照射提供依据。

The Measurement and Analysis of the Dosimetry of Total Skin Electron Irradiation.

Objective To measure the dosimetry of Total Skin Electron Irradiation.Methods Varian23EX linear accelerator was used to produce electron.Dosimetric characteristics in SSD 400cm were measured with parallel-plate chamber,film,TLD,by using the six-dual fields technique.Results A uniformity of ±5% of the treatment plane is achievable.In single field,the skin dose was more than 80%,depth of the max dose was 0.6cm,depth of 80% and 50% dose were 1.10cm and 1.42cm.For six-dual fields,depth of the max dose was nearly on the skin,depth of 80% and 50% dose were 0.40cm and 1.00cm.The X-ray contamination was less than 2.2%.Multiplication factor was 3.05.Conclusion The dosimetric characteristics in TSET were much different from the general single beam.The measurement before the treatment is necessary.