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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。
Objective To measure the dosimetric parameters of electron beam whole body skin irradiation. Methods The dosimetry parameters of 6 MeV electron beam at the source skin distance of 400 cm were measured on a Varian 23EX accelerator using a parallel-plate ionization chamber, a film, a thermoluminescence element and the like. Results The dose field uniformity in the treatment plane reached ± 5%. Single table radiation dose of 80% or more, the maximum depth of 0.6cm, 80% and 50% of the dose depth were 1.10cm and 1.42cm. The maximum dose depth of the two-rack six-field close to the skin surface, 80% and 50% dose depth of 0.40cm and 1.00cm respectively. X-ray pollution was 2.2%. The cumulative factor average of 3.05. Conclusion Under the condition of whole-body electron beam irradiation, the dose characteristics of electron beam are quite different from those under normal conditions. Therefore, it is necessary to provide the basis for clinical irradiation through actual measurement.