Monte Carlo simulation of the effect of magnetic fields on brachytherapy dose distributions in lung tissue material.
Monte Carlo simulation of the effect of magnetic fields on brachytherapy dose distributions in lung tissue material.
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DOI：
10.1371/journal.pone.0238704
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发表时间：
2020
期刊：
影响因子：
3.7
通讯作者：
Ramos-Méndez J
中科院分区：
文献类型：
--
作者：
Moreno-Barbosa F;de Celis-Alonso B;Moreno-Barbosa E;Hernández-López JM;Geoghegan T;Ramos-Méndez J
这项工作的目的是使用TOPAS蒙特卡罗模拟磁场对理想和临床条件下近距离放射治疗肺治疗剂量分布的影响。理想主义的研究进行了建模，包括一个单能电子源的432千电子伏，或多能电子源，使用光谱的二次电子产生的192 Ir γ射线照射。电子源位于均匀肺组织体模（ρ = 0.26 g/cm 3）的中心。相反，临床研究使用VariSource VS 2000 192 Ir源在患有肺肿瘤的患者中进行模拟。考虑了三个轮廓体积：肿瘤、计划肿瘤体积（PTV）和肺。在所有研究中，在存在或不存在3 T恒定磁场的情况下计算剂量分布。此外，计算了VariSource的TG-43参数，并将其与EGS-brachy（EGSnrc）和PENDIX PE的已发表数据进行了比较。在理想研究中，磁场影响剂量分布。对于单能和多能研究，在磁场存在下，10%等剂量线的径向距离分别减少了64.9%和24.6%。对于临床研究，磁场导致患者剂量分布平均差异为10%。然而，剂量-体积直方图的差异低于2%。最后，对于TG-43参数，TOPAS的剂量率常数分别与EGS-brachy和PENTHESPE相差0.09% ± 0.33%和0.18% ± 0.33%。几何形状和各向异性函数的差异分别在1.2% ± 1.1%和0.0% ± 0.3%以内。在192 Ir近距离放射治疗肺部期间，3 T磁共振机器内的洛伦兹力不足以显著影响肿瘤剂量分布，正如预期的那样。然而，在肺组织中发现了较大的局部差异。因此，这种效应的应用受到以下事实的限制，即有意义的差异仅出现在含有空气的区域中，而空气在人体内并不丰富。
The aim of this work was to use TOPAS Monte Carlo simulations to model the effect of magnetic fields on dose distributions in brachytherapy lung treatments, under ideal and clinical conditions. Idealistic studies were modeled consisting of either a monoenergetic electron source of 432 keV, or a polyenergetic electron source using the spectrum of secondary electrons produced by 192Ir gamma-ray irradiation. The electron source was positioned in the center of a homogeneous, lung tissue phantom (ρ = 0.26 g/cm3). Conversely, the clinical study was simulated using the VariSource VS2000 192Ir source in a patient with a lung tumor. Three contoured volumes were considered: the tumor, the planning tumor volume (PTV), and the lung. In all studies, dose distributions were calculated in the presence or absence of a constant magnetic field of 3T. Also, TG-43 parameters were calculated for the VariSource and compared with published data from EGS-brachy (EGSnrc) and PENELOPE. The magnetic field affected the dose distributions in the idealistic studies. For the monoenergetic and poly-energetic studies, the radial distance of the 10% iso-dose line was reduced in the presence of the magnetic field by 64.9% and 24.6%, respectively. For the clinical study, the magnetic field caused differences of 10% on average in the patient dose distributions. Nevertheless, differences in dose-volume histograms were below 2%. Finally, for TG-43 parameters, the dose-rate constant from TOPAS differed by 0.09% ± 0.33% and 0.18% ± 0.33% with respect to EGS-brachy and PENELOPE, respectively. The geometry and anisotropy functions differed within 1.2% ± 1.1%, and within 0.0% ± 0.3%, respectively. The Lorentz forces inside a 3T magnetic resonance machine during 192Ir brachytherapy treatment of the lung are not large enough to affect the tumor dose distributions significantly, as expected. Nevertheless, large local differences were found in the lung tissue. Applications of this effect are therefore limited by the fact that meaningful differences appeared only in regions containing air, which is not abundant inside the human.
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影响因子：
10
作者：
FROMSON, BH;DENISON, DM
通讯作者：
DENISON, DM
影响因子：
3.7
作者：
Grove O;Berglund AE;Schabath MB;Aerts HJ;Dekker A;Wang H;Velazquez ER;Lambin P;Gu Y;Balagurunathan Y;Eikman E;Gatenby RA;Eschrich S;Gillies RJ
通讯作者：
Gillies RJ
影响因子：
3.8
作者：
Chen, Y;Bielajew, AF;Becchetti, FD
通讯作者：
Becchetti, FD
影响因子：
3.5
作者：
Raaijmakers, A. J. E.;Raaymakers, B. W.;Lagendijk, J. J. W.
通讯作者：
Lagendijk, J. J. W.
DOI：
10.1016/0168-583x(95)00349-5
发表时间：
1995-05-01
影响因子：
1.3
作者：
BARO, J;SEMPAU, J;SALVAT, F
通讯作者：
SALVAT, F