The effect of source-axis distance on integral dose: implications for IMRT.
The effect of source-axis distance on integral dose: implications for IMRT.
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源轴距离对积分剂量的影响：对 IMRT 的影响。
DOI：
10.1007/bf03178356
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发表时间：
2001
影响因子：
--
通讯作者：
Keall,P
中科院分区：
文献类型：
--
作者：
Keall,P
源-轴距离(SAD)是影响整体剂量、剂量率和患者清除的治疗机设计参数。这项工作的目的是研究源-轴距离对适形弧光治疗积分剂量的影响。这项工作是一个更大项目的一部分，该项目旨在确定专用调强放射治疗机器的理想特性。在适形弧疗中，测定SAD对束流能量、PTV大小、身体大小和PTV位置的敏感性。对于这里进行的计算，假设剂量等于Terma。采用积分剂量比(IDR)对计算结果进行量化。结果表明，虽然IDR对SAD的依赖性随着能量的增加而减小，但IDR随着SAD和光子能量的增加而增大。PTV的大小对SAD和IDR之间的关系的影响可以忽略不计，但身体大小确实影响SAD和DR之间的关系。PTV在体内的位置也影响DR。从剂量学角度考虑，SAD越大，可能的剂量分布越好。与100厘米SAD的IDR相比，非常大的SAD的IDR增加了大约5%。类似地，100厘米SAD的IDR大约比50厘米SAD的IDR高5%。
The source-axis distance (SAD) is a treatment machine design parameter that affects integral dose, dose rate and patient clearance. The aim of this work was to investigate the effect of source-axis distance on integral dose for conformal arc therapy. This work is part of a larger project to determine the ideal characteristics of a dedicated IMRT machine. The sensitivity of SAD to beam energy, PTV size, body size and PTV position were determined for conformal arc therapy. For the calculations performed here it was assumed that dose equals terma. The integral dose ratio (IDR) was used to quantify the calculation results. It was found that the IDR increases as both SAD and photon energy increase, though the dependence of IDR on SAD decreases as energy increases. The PTV size was found to have a negligible effect on the relationship between the SAD and IDR, however the body size does affect the relationship between the SAD and DR. The position of the PTV within the body also affects the DR. From dosimetric considerations alone, the larger the SAD, the better the possible dose distribution. The IDR for a very large SAD is increased by approximately 5% when compared with the IDR for 100 cm SAD. Similarly, the IDR for 100 cm SAD is approximately 5% higher than the IDR at 50 cm SAD.