多叶准直器叶片宽度对容积旋转调强放疗剂量分布的影响

发布时间：2018-05-01 16:12

本文选题：多叶准直器 + 容积旋转调强放疗　；参考：《中国医学物理学杂志》2016年11期

【摘要】：目的:研究多叶准直器(MLC)叶片宽度在容积旋转调强放疗(VMAT)中对剂量分布的影响。方法:选取头部肿瘤患者12例,划分成大靶区体积(脑胶质瘤)组和小靶区体积(垂体瘤)组。在Eclipse治疗计划系统中,对每例患者使用相同的剂量学限制条件,并将肿瘤靶区置于窄MLC叶片(5mm)区和宽MLC叶片(10mm)区,分别制定两个VMAT治疗计划。通过计算对比剂量分布图和剂量学指标,分析MLC叶片宽度对不同靶区体积肿瘤剂量分布的影响。结果:无论是大体积靶区肿瘤还是小体积靶区肿瘤,使用较窄的MLC叶片都可以改善剂量学指标,但是这种改进不具有统计学差异(P0.05)。而对于给定宽度(5mm或10mm)的MLC叶片,大体积靶区肿瘤组的VMAT治疗计划剂量学指标优于小体积靶区肿瘤组,并且具有统计学差异(P0.05);另一方面,随着肿瘤体积的减小,剂量学指标的改进率明显提高。结论:VMAT放疗技术可以改善剂量学指标,并且能够有效减小MLC叶片宽度对剂量分布的影响;靶区体积的大小是影响VMAT治疗计划剂量学指标改进率的重要因素。在VMAT临床应用中,应根据肿瘤靶区体积大小及其与危及器官的位置关系,合理选择MLC叶片厚度以达到最佳疗效。
[Abstract]:Aim: to study the effect of blade width of multileaf collimator MLC on dose distribution in VMATT. Methods: 12 patients with head tumor were divided into two groups: large target volume (glioma) and small target volume (pituitary adenoma). In the Eclipse treatment planning system, each patient was given the same dosimetric restriction, and the tumor target was placed in the narrow MLC leaf area (5 mm) and the wide MLC leaf area (10 mm). Two VMAT treatment plans were made respectively. The effects of leaf width of MLC on the dose distribution of tumor in different target areas were analyzed by comparing the dose distribution map and dosimetry index. Results: both large and small target tumors could improve dosimetric indices by using narrow MLC leaves, but there was no statistical difference in this improvement. For the MLC leaves with a given width of 5 mm or 10 mm, the dose indices of the VMAT treatment plan in the mass target tumor group were better than those in the small volume target tumor group, and the difference was statistically significant (P 0.05); on the other hand, with the decrease of tumor volume, The improvement rate of dosimetric index was improved obviously. Conclusion the dose index can be improved and the effect of leaf width of MLC on dose distribution can be effectively reduced by using the technique of: VMAT, and the volume of target area is an important factor affecting the improvement rate of dosimetric index in VMAT treatment plan. In clinical application of VMAT, we should choose the thickness of MLC leaf reasonably according to the volume of tumor target and the relationship between the volume of tumor target and the location of the organ at risk to achieve the best curative effect.
【作者单位】：武汉大学物理科学与技术学院;武汉大学中南医院放疗科;克拉玛依市中心医院血液肿瘤科;
【基金】：国家自然科学基金(10875092) 湖北省自然科学基金(2012FKB04449)
【分类号】：R730.55

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