电子束限束筒挡铅后的剂量学效应

本文探讨了挡船对电子束限束筒输出剂量的影响。采用标准水模及IONX2500／3型剂量仪，0.6cm^3电离室，对Philips SL75-14型直线加速器不同能量电子束固定限束筒、等效方野公式推算所得相应限束筒不规则野的吸收剂量进行了实测。结果分析：在限束筒上加空心铅块所获得的等效方野与该限束筒的吸收剂量无明显差别，但与等效方野公式推算所得相应限束筒的吸收剂量差别显著。因此我们认为：用不规则野电子束治疗时，应选用原限束筒的剂量学参数，不宜用等效方野公式推算所得相应限束筒的剂量学参数。

Effect of blocking on electrons beams applicator absorbed dose

Aim: To evaluate the effect of blocking leading influence the absorbed dose of electrons beams applicator.Metaods: Using 0.6 cm3 ionization and standard model and IONX2500/3 meter to measure absorbed dose of different energy electrons beams fixed applicator of Philips SL75-14 linear accelerator and also the dose of irregularly electrons beams applicator calculate by equivalent squares equation in this research. Results: Results show that absorbed dose of blocking leading electrons beams applicator has no relationship with equal squares,but has absolute difference with the calculate one. Conclusion: When treated by the irregularly electrons beams using original dose parameters of electrons beams applicator,donot use the dose parameters of electrons beams applicator which calculate by equivalent squares equation.