Tryggestad E, Armour M, Iordachita I, Verhaegen F, Wong J W
Deptartment of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD, USA.
Phys Med Biol. 2009 Sep 7;54(17):5341-57. doi: 10.1088/0031-9155/54/17/017. Epub 2009 Aug 18.
Our group has constructed the small animal radiation research platform (SARRP) for delivering focal, kilo-voltage radiation to targets in small animals under robotic control using cone-beam CT guidance. The present work was undertaken to support the SARRP's treatment planning capabilities. We have devised a comprehensive system for characterizing the radiation dosimetry in water for the SARRP and have developed a Monte Carlo dose engine with the intent of reproducing these measured results. We find that the SARRP provides sufficient therapeutic dose rates ranging from 102 to 228 cGy min(-1) at 1 cm depth for the available set of high-precision beams ranging from 0.5 to 5 mm in size. In terms of depth-dose, the mean of the absolute percentage differences between the Monte Carlo calculations and measurement is 3.4% over the full range of sampled depths spanning 0.5-7.2 cm for the 3 and 5 mm beams. The measured and computed profiles for these beams agree well overall; of note, good agreement is observed in the profile tails. Especially for the smallest 0.5 and 1 mm beams, including a more realistic description of the effective x-ray source into the Monte Carlo model may be important.
我们团队构建了小动物辐射研究平台（SARRP），用于在锥束CT引导下，通过机器人控制向小动物体内的靶点提供聚焦千伏级辐射。目前的工作旨在支持SARRP的治疗计划能力。我们设计了一个全面的系统来表征SARRP在水中的辐射剂量学，并开发了一个蒙特卡罗剂量引擎，以重现这些测量结果。我们发现，对于尺寸从0.5到5毫米的可用高精度光束组，SARRP在1厘米深度处提供了102至228 cGy min(-1)的足够治疗剂量率。在深度剂量方面，对于3毫米和5毫米光束，在0.5至7.2厘米的整个采样深度范围内，蒙特卡罗计算值与测量值之间的绝对百分比差异平均值为3.4%。这些光束的测量和计算轮廓总体上吻合良好；值得注意的是，在轮廓尾部观察到了良好的一致性。特别是对于最小的0.5毫米和1毫米光束，在蒙特卡罗模型中纳入更真实的有效X射线源描述可能很重要。
