Monte Carlo calculation of kerma to a point in the vicinity of media interfaces.
Monte Carlo calculation of kerma to a point in the vicinity of media interfaces.
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蒙特卡罗计算介质界面附近点的比释动能。
DOI：
10.1088/0031-9155/38/12/009
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发表时间：
1993
影响因子：
3.5
通讯作者：
Perera,H
中科院分区：
文献类型：
--
作者：
Li,Z;Williamson,JF;Perera,H
最近的研究表明，蒙特卡罗光子输运（MCPT）模拟是一种实用而准确的剂量学工具，用于表征复杂三维（3D）几何形状下的近距离治疗剂量分布。由于在此应用中遇到陡峭的剂量梯度，估计算法的选择，即从单个光子历史中提取剂量估计的算法，对于确保足够的空间分辨率和计算效率至关重要。虽然传统的MCPT剂量估计技术在许多情况下足够准确，但由于感兴趣点位于介质界面附近，它们不可避免地会失败，因为它们要求感兴趣点被直径几毫米的均匀介质区域所包含。这严重限制了MCPT在近距离放射剂量测定中的应用领域，并妨碍了在诸如妇科涂抹器中铅屏蔽体后面的点进行剂量估计，或模拟小型复杂结构检测器响应。我们已经成功地将一个中子通量估计器——单次碰撞通量估计器（OMCFE）适应于MCPT码，克服了这个问题。OMCFE源自我们熟悉的下一次飞行估计算法，并且通过使用光子轨迹重采样方案，在感兴趣点不需要均匀介质。因此，它是一个真正的点剂量估计器。针对各种一维和三维基准问题对OMCFE进行了测试。这些基准包括30和600 keV的单能量点源，以及3M型号6702 125 I种子，137 Cs管和192 Ir种子，其几何形状近似于常见的近距离治疗剂量学问题。在解决这些基准问题时，OMCFE与传统的MCPT剂量估计算法非常一致，而且在许多情况下效率更高。
Recent work has demonstrated that Monte Carlo photon transport (MCPT) simulation is a practical and accurate dosimetry tool for characterizing brachytherapy dose distributions in the presence of complex three-dimensional (3D) geometries. Because of the steep dose gradients encountered in this application, the choice of estimation algorithm, ie, the algorithm for extracting dose estimates from individual photon histories, is critical to ensure adequate spatial resolution and computational efficiency. While conventional MCPT dose estimation techniques are sufficiently accurate in many cases, they inevitably fail with the point of interest is located near media interfaces, since they require the point of interest to be contained by a region of homogeneous medium of several millimetres in diameter. This severely limits the domain of application of MCPT in brachytherapy dosimetry and prevents dose estimation at points such as those immediately behind lead shields contained in gynaecological applicators, or simulation of small intricately structured detector response. We have successfully adapted to an MCPT code a neutron-flux estimator, the one-more-collided flux estimator (OMCFE), which overcomes this problem. OMCFE is derived from the familiar next-flight estimation algorithm, and, through the use of a photon trajectory resampling scheme, does not require homogeneous media at the point of interest. it is therefore a true point-dose estimator. OMCFE was tested against a variety of one-and three-dimensional benchmark problems. These benchmarks included mono-energetic point sources of 30 and 600 keV, as well as a 3M model 6702 125 I seed, a 137 Cs tube, and an 192 Ir seed in geometries approximating common brachytherapy dosimetric problems. OMCFE agrees closely with conventional MCPT dose estimation algorithms in solving these benchmark problems, while in many cases being much more efficient.
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125I 种子的剂量率测定。
影响因子：
3.8
作者：
Chiu-Tsao,ST;Anderson,LL;O'Brien,K;Sanna,R
通讯作者：
Sanna,R
用于辐射传输计算的基于体积的几何建模。
影响因子：
3.8
作者：
Li,Z;Williamson,JF
通讯作者：
Williamson,JF
一个或多个探测器的某一点通量的有界估计
DOI：
--
发表时间：
1974
期刊：
影响因子：
--
作者：
H. Steinberg;C. Hytry
通讯作者：
C. Hytry
影响因子：
3.8
作者：
WILLIAMSON, JF
通讯作者：
WILLIAMSON, JF
MCN：中子蒙特卡罗代码
DOI：
--
发表时间：
1972
期刊：
影响因子：
--
作者：
E. Cashwell;J. Neergaard;W. M. Taylor;G. D. Turner
通讯作者：
G. D. Turner