多叶光栅叶片宽度对鼻咽癌剂量学的影响  

The Dosimetric Impact of Multi Leaf Collimator Leaf Width on Nasopharyngeal Carcinoma Intensity Modulated Radiotherapy

作　　者：桑勇[1] 陈维军[1] 狄小云[1] 王彬冰[1] 祝成龙[1] 徐敏[1] 翁邓胡[1] 

机构地区：[1]浙江省肿瘤医院放疗科放射物理室,浙江省放射肿瘤重点实验室,浙江杭州310022

出　　处：《中国医学物理学杂志》2014年第6期5240-5243,共4页Chinese Journal of Medical Physics

摘　　要：目的:评估加速器治疗机多叶光栅(MLC)叶片宽度在鼻咽癌调强放疗中的剂量学影响。方法:建立两个直线加速器治疗机模型:两个模型的剂量学参数完全一致,将多叶光栅宽度分别设置为10 mm和5 mm,其余机械参数也完全一致;将这两个治疗机模型应用于7例鼻咽癌患者的调强放疗计划设计,比较不同的多叶光栅叶片宽度对鼻咽癌调强放疗计划带来的剂量学影响。结果:使用10 mm MLC叶片宽度的模型和5 mm MLC叶片宽度的模型制定调强放疗计划,其脑干最大剂量分别为54.5 Gy±3.4 9 Gy和53.5 Gy±3.67 Gy,左侧视神经最大剂量分别为43.6 Gy±15.5 Gy和42.5 Gy±15.3 Gy,右侧视神经最大剂量分别为40.8 Gy±16.3 Gy和39.6 Gy±16.4 Gy,左侧颞叶大于65 Gy的体积分别为0.58 cm3±0.57cm3和0.48 cm3±0.46 cm3。对于几例脑干受侵和视神经视交叉受侵的鼻咽癌病人,使用5 mm MLC叶片宽度相比10 mm MLC叶片宽度的机器模型,能够明显的降低其对应受侵部位的高剂量,且能带来更好的靶区剂量均匀性。结论:5 mm MLC叶片宽度治疗机相对于10 mm MLC叶片宽度治疗机,更适合对危及器官有高剂量要求的鼻咽癌的放射治疗。Objective： To evaluate the dos!e effects of leaf width of accelerator treatment machine multi leaf collimator on intensity modulated radiotherapy. Methods： Two accelerator radiotherapy machine were modeled with 10ram and 5 ram leaf width of MLC leaf respectively. The dosimetric distributions were compared between the two models for the seven patients with nasopharyngeal carcinoma. Results： The max dose of brainstem was 54.5 Gy ±3.49 Gy and 53.5 Gy ±3.67 Gy respectively, the max dose of left optic nerve was 43.6 Gy± 15.5 Gy and 42.5 Gy±15.3 Gy respectively, the max dose of right optic nerve was 40.8 Gy± 16.3 Gy and 39.6 Gy_± 16.4 Gy respectively, the volume of left temporal lobe greater than 65 Gy was 0.58cm^3±0.57cm^3 and 0.48 cm^3±0.46 cm^3 respectively. Lower high dose can be achieved by 5 mm leaf width than 10 mm leaf width for the patients whose brainstem or optic chiasm was involved. Better homogeneity index （HI） can be achieved by accelerator with 5 mm leaf width than 10 mm leaf width. Conclusions： The accelerator with 5 mm MLC leaf width is more suitable for the nasopharyngeal carcinoma（NPC） patients whose target and organs at risk had higher dosage requirements than the accelerator with 10 mm MLC leaf width.

关 键 词：调强放射治疗 鼻咽癌 多叶光栅 叶片宽度 

分 类 号：R730.55[医药卫生—肿瘤]