Pantelis Evaggelos, Baltas Dimos, Dardoufas Konstantinos, Karaiskos Pantelis, Papagiannis Panagiotis, Rosaki-Mavrouli Heleni, Sakelliou Loukas
Nuclear and Particle Physics Section, Physics Department, Medical School, Areteion Hospital, University of Athens, Athens, Greece.
Int J Radiat Oncol Biol Phys. 2002 Jul 15;53(4):1071-84. doi: 10.1016/s0360-3016(02)02804-3.
To investigate the efficacy of a Sievert integration model in dosimetry close to 192Ir high-dose-rate brachytherapy sources and validate its accuracy and potential to resolve dosimetric differences between these sources in the cm and mm distance ranges relevant to interstitial and intravascular brachytherapy applications, respectively.
The dosimetric quantities of the generalized Task Group 43 formalism, as well as dose rate profiles in polar and Cartesian coordinates, are calculated, and results are compared to corresponding Monte Carlo data in the literature.
Sievert calculations were found in excellent agreement with corresponding Monte Carlo published results. Dose rate polar angle profiles in the cm distance range depended significantly on corresponding anisotropy function data, whereas in the mm distance range, dose rate polar angle profiles are governed by the corresponding geometry function profiles, because anisotropy proved insignificant. Radial dose functions of the sources were found comparable. A simple equation for the calculation of the dose rate constant of the sources within clinically acceptable accuracy is provided.
The particular Sievert model proved capable of resolving dosimetric differences of the sources and provides results within clinical accuracy. Therefore, it constitutes a useful tool for dosimetry in clinical practice and especially in intravascular applications, where there is currently a lack of available dosimetric data.
研究西弗积分模型在靠近192Ir高剂量率近距离放射治疗源的剂量测定中的有效性，并验证其在厘米和毫米距离范围内分别解决这些源之间剂量差异的准确性和潜力，这些距离范围分别与间质和血管内近距离放射治疗应用相关。
计算广义任务组43形式主义的剂量学量以及极坐标和笛卡尔坐标中的剂量率分布，并将结果与文献中相应的蒙特卡罗数据进行比较。
发现西弗计算结果与相应的已发表蒙特卡罗结果非常一致。在厘米距离范围内，剂量率极角分布显著依赖于相应的各向异性函数数据，而在毫米距离范围内，剂量率极角分布由相应的几何函数分布决定，因为各向异性被证明不显著。发现源的径向剂量函数具有可比性。提供了一个在临床可接受精度内计算源的剂量率常数的简单方程。
特定的西弗模型被证明能够解决源的剂量差异问题，并提供临床精度内的结果。因此，它构成了临床实践中剂量测定的有用工具，特别是在目前缺乏可用剂量数据的血管内应用中。
