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电子调强放射治疗浅表肿瘤优于光子调强放射治疗,但光子调强放射治疗中光子的多叶准直器不适用,需专门的电子多叶准直器EMLC。用Monte Carlo模拟计算研究EMLC叶片的材料、厚度、端面形状和宽度等对剂量的影响。计算结果表明,W比Pb、Fe、Cu更适合做EMLC材料,且厚度2cm时足以挡住大部分电子,并产生相对较少的轫致辐射;直立端面作EMLC叶片端面时会产生较小剂量半影,并在射野边缘有更好平坦度;电子束通过宽度5mm的EMLC叶片比1cm的射野边缘剂量明显增加,但宽度太大不利于准确控制子野形状,因此选择1cm作EMLC叶片宽度较优。
Electronically modulated radiation therapy for superficial tumors is superior to photon intensity modulated radiation therapy. However, the photon multilobular collimator is not suitable for photon intensifying radiation therapy, and a special electronic multileaf collimator EMLC is required. Monte Carlo simulation was used to study the effects of material, thickness, shape and width of EMLC on dose. The calculated results show that W is more suitable than Pb, Fe and Cu for the EMLC material, and it is enough to block most of the electrons at the thickness of 2cm and produce relatively less bremsstrahlung. When the upright end surface is used as the EMLC blade end surface, And the edge of the radio field has a better flatness; electron beam through the 5mm width of the EMLC leaf blade edge than 1cm radiation dose significantly increased, but the width is not conducive to accurately control the shape of the son field, so choose 1cm as EMLC blade width Better.