TrueBeam加速器多叶准直器射野剂量学特性

发布时间：2018-03-27 08:31

本文选题：未均整射束　切入点：多叶准直器　出处：《核技术》2015年10期

【摘要】：医用电子直线加速器未均整射束的剂量学特征和优势早已被证明,但是随着三维适形和调强放射治疗技术的发展,临床治疗的射野(Field)主要是由多叶准直器射野形成,而有关未均整射束的多叶准直器射野剂量特征的研究很少。本文研究True Beam加速器6 MV-X未均整射束的多叶准直器射野剂量特征。利用蒙特卡罗(Monte Carlo,MC)模拟和三维剂量扫描系统临床测量,对比和分析射野离轴比曲线剂量特征。结果表明:蒙特卡罗模拟和临床测量未均整射束下多叶准直器叶片到位精度、X和Y方向的漏射量、射野半影、叶片间凹凸结构对射野剂量的影响大体一致。多叶准直器形成不规则射野的几何学、蒙特卡罗模拟和临床测量的不符合度(MC或临床测量50%等剂量曲线的面积与射野几何面积的差值相对于射野实际面积的百分数)分别为3.629%、3.262 6%和2.039 4%。圆形射野、具有凹凸边界射野几何学和蒙特卡罗模拟的不符合度分别为0.866 2%、0.879 4%和0.231 4%、0.817 0%。为未均整射束条件下多叶准直器的临床合理使用提供可靠的依据。
[Abstract]:The dosimetric characteristics and advantages of medical electron linear accelerator inhomogeneous beam have long been proved, but with the development of three-dimensional conformal and intensity modulated radiation therapy, the field field of clinical treatment is mainly formed by multi-leaf collimator. In this paper, the dose characteristics of multi-leaf collimator in 6 MV-X True Beam accelerator are studied. Monte Carlo Monte Carlo method is used to simulate and 3D dose. Scanning system clinical measurement, The dose characteristics of off-axis ratio curve of field were compared and analyzed. The results showed that Monte Carlo simulation and clinical measurement of leakage quantity and field penumbra in X and Y directions of multi-leaf collimator blade under uneven integrated beam, The effect of the concave and convex structures on the field dose is almost the same. The geometry of the irregular field formed by the multi-leaf collimator. The difference between the area of 50% isodose curve and the geometric area of the ejection field in Monte Carlo simulation and clinical measurement is 3.629% and 2.039 4% respectively, and the difference between the area of 50% isodose curve and the geometric area of the field is 3.262 6% and 2.039 4% respectively. The nonconformities of concave and convex boundary field geometry and Monte Carlo simulation are 0.866 and 0.231 respectively, which provide a reliable basis for the rational use of multileaf collimator under the condition of uneven beam.
【作者单位】：上海大学环境与化学工程学院;中国科学院上海应用物理研究所;中南大学湘雅三医院;
【基金】：国家自然科学基金(No.11175112)资助
【分类号】：R814.2

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