Dosimetric characteristics of a low-kV intra-operative x-ray source: Implications for use in a clinical trial for treatment of low-risk breast cancer
Dosimetric characteristics of a low-kV intra-operative x-ray source: Implications for use in a clinical trial for treatment of low-risk breast cancer
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DOI：
10.1118/1.1595611
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发表时间：
2003-09-01
期刊：
影响因子：
3.8
通讯作者：
Carruthers, B
中科院分区：
文献类型：
--
作者：
Ebert, MA;Carruthers, B
检查了用于进行术中辐照的低kV X射线设备Intrabeam（Photoelectron Corporation，列克星敦，MA）的剂量测定特性。两个剂量模型被认为是一个分析模型，只考虑初级X射线束，和蒙特卡罗模型，利用EGSnrc代码和球形模拟几何。两种模型均证明可可靠验证器械的测量剂量分布。蒙特卡罗模型是必要的检查光谱变化和不均匀性的影响。蒙特卡洛模型的预测用于检查在低风险乳腺癌的术中、单次切除术后治疗中使用Intrabeam的多中心临床试验的考虑要点。当使用水中剂量下降数据时，乳腺组织和水的放射等效性的预测差异表明乳腺组织的剂量不足3-5%（在50 kV射束中）。骨中的显著剂量增加（即，肋骨），但根据已发表的放射性肋骨骨折的临床数据，可以得出结论，放射性肋骨骨折的诱导不会造成重大风险。检查剂量-体积随治疗区域（由切除体积的大小定义）大小的变化，表明在可能的“靶”体积范围内剂量-体积特征存在较大变化。(C)2003年美国医学物理学家协会。
The dosimetric characteristics of a low-kV x-ray device for performing intra-operative irradiations, the Intrabeam (Photoelectron Corporation, Lexington, MA), are examined. Two dosimetric models are considered-an analytical model considering only the primary x-ray beam, and a Monte Carlo model utilizing the EGSnrc code and a spherical simulation geometry. Both models prove reliable for verifying measured dose distributions for the device. The Monte Carlo model is necessary for examining spectral variations and the influence of inhomogeneities. The predictions of the Monte Carlo model are utilized to examine points of consideration for a multi-center clinical trial using the Intrabeam in the intra-operative, single fraction post-resection treatment of low-risk breast cancer. Predicted differences in radiological equivalence of breast tissue and water suggest a 3-5% under-dose of breast tissue (in a 50 kV beam) when dose fall-off data in water is used. A substantial dose enhancement in bone (i.e., ribs) adjacent to the treatment site is predicted though, based on published clinical data for radiation-induced rib fracture, it is concluded that induction of radiation-induced rib fracture would not pose a significant risk. Dose-volume changes with size of the treatment area (defined by the size of the resection volume) are examined indicating large variations in dose-volume characteristics across the range of possible "target" volumes. (C) 2003 American Association of Physicists in Medicine.