Investigation of the effects of treatment planning variables in small animal radiotherapy dose distributions.
Investigation of the effects of treatment planning variables in small animal radiotherapy dose distributions.
复制标题
研究治疗计划变量对小动物放射治疗剂量分布的影响。
DOI：
10.1118/1.3276738
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发表时间：
2010
期刊：
影响因子：
3.8
通讯作者：
Graves,EdwardE
中科院分区：
文献类型：
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作者：
Motomura,AmyR;Bazalova,Magdalena;Zhou,Hu;Keall,PaulJ;Graves,EdwardE
小动物放射治疗的方法还没有达到与临床放射治疗相同的剂量靶向。为了了解如何更好地规划小动物辐射使用最近开发的系统，为此目的，作者的特点是从适形放射治疗的小动物在microCT扫描仪配备了一个可变孔径collimator.MethodsDose distributions提供给一个圆柱形的固体水幻影使用Monte Carlo算法进行了模拟。使用BEAMnrc软件生成120 kVp X射线束和等中心处1-10 mm准直器宽度的相空间文件，并在DOSXYZnrc中为各种靶生成编号为5 - 80的均匀间隔射束的剂量分布，包括各种尺寸范围内的居中球形靶、偏离居中不同距离的球形靶和各种椭球体靶。使用剂量体积直方图分析剂量分布。传递到一只小鼠的剂量也进行了模拟，并产生了肿瘤，心脏，左肺，右肺，和spinal cord.ResultsResults的剂量体积直方图表明，为中心，对称的目标，实现一个平滑的剂量体积直方图所需的光束的数量随着目标尺寸的增加而减少。非中心对称目标的剂量分布没有表现出任何显着的保形性损失与增加从体模中心的偏移，表明足够的射束穿透体模从所有角度瞄准浅表目标。即使可变的准直器宽度，瞄准不对称的目标被发现有较少的保形性比球形目标。照射的小鼠肺肿瘤与多个波束宽度被发现有效地提供剂量的肿瘤体积，同时最大限度地减少剂量到其他criticalstructure.ConclusionsOverall，这种方法产生和分析剂量分布提供了一个定量的方法，为小动物放射治疗规划制定实用的指导方针。未来的工作应解决的方法，以提高一致性的不对称目标。
PurposeMethods used for small animal radiation treatment have yet to achieve the same dose targeting as in clinical radiation therapy. Toward understanding how to better plan small animal radiation using a system recently developed for this purpose, the authors characterized dose distributions produced from conformal radiotherapy of small animals in a microCT scanner equipped with a variable‐aperture collimator.MethodsDose distributions delivered to a cylindrical solid water phantom were simulated using a Monte Carlo algorithm. Phase‐space files for 120 kVp x‐ray beams and collimator widths of 1–10 mm at isocenter were generated using BEAMnrc software, and dose distributions for evenly spaced beams numbered from 5 to 80 were generated in DOSXYZnrc for a variety of targets, including centered spherical targets in a range of sizes, spherical targets offset from centered by various distances, and various ellipsoidal targets. Dose distributions were analyzed using dose volume histograms. The dose delivered to a mouse bearing a spontaneous lung tumor was also simulated, and dose volume histograms were generated for the tumor, heart, left lung, right lung, and spinal cord.ResultsResults indicated that for centered, symmetric targets, the number of beams required to achieve a smooth dose volume histogram decreased with increased target size. Dose distributions for noncentered, symmetric targets did not exhibit any significant loss of conformality with increasing offset from the phantom center, indicating sufficient beam penetration through the phantom for targeting superficial targets from all angles. Even with variable collimator widths, targeting of asymmetric targets was found to have less conformality than that of spherical targets. Irradiation of a mouse lung tumor with multiple beam widths was found to effectively deliver dose to the tumor volume while minimizing dose to other critical structures.ConclusionsOverall, this method of generating and analyzing dose distributions provides a quantitative method for developing practical guidelines for small animal radiotherapy treatment planning. Future work should address methods to improve conformality in asymmetric targets.