Backscatter factors and mass energy-absorption coefficient ratios for diagnostic radiology dosimetry
Backscatter factors and mass energy-absorption coefficient ratios for diagnostic radiology dosimetry
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DOI：
10.1088/0031-9155/56/22/012
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发表时间：
2011-11-21
影响因子：
3.5
通讯作者：
Andreo, Pedro
中科院分区：
文献类型：
--
作者：
Benmakhlouf, Hamza;Bouchard, Hugo;Andreo, Pedro
使用蒙特卡罗模拟计算了用于确定诊断放射学中表面剂量的反向散射因子 B 和质量能量吸收系数比 (mu(en)/rho)(omega,)（空气）。主要目的是将可用数据的范围扩展到现代 X 射线技术中使用的质量，特别是介入放射学。为 15 厘米厚的水体模创建了 4 至 150 keV 之间的单能光子和不同场尺寸的综合数据库。使用 PENELOPE Monte Carlo 系统计算后向散射光谱，对能量中的轨迹长度注量差异进行评分，统计不确定性可忽略不计；使用蒙特卡罗计算光谱、B 因子和 (mu(en)/rho)(omega)，然后对每种能量进行数值计算。随后使用加权平均程序将事件临床光谱与单能量数据进行卷积。该方法以事件临床光谱的完整蒙特卡罗计算为基准，获得 0.3-0.6% 范围内的差异。所使用的技术可以计算任何入射光谱的 B 和 (mu(en)/rho)(w)、空气，而无需进一步耗时的蒙特卡罗模拟。通过详细的比较，证实了扩展的剂量测定数据比目前可用的剂量测定数据适用于更广泛的临床质量，同时与现有数据保持一致。将单能值和光谱平均值与已发表的数据（包括 ICRU 报告 74 和 IAEA TRS-457 中的数据）进行比较，发现平均差异为 0.6%。结果以适合临床使用的综合表格形式提供。使用设计的 GUI 界面结合软件生成入射光子光谱，可以轻松计算附加质量。
Backscatter factors, B, and mass energy-absorption coefficient ratios, (mu(en)/rho)(omega,) (air), for the determination of the surface dose in diagnostic radiology were calculated using Monte Carlo simulations. The main purpose was to extend the range of available data to qualities used in modern x-ray techniques, particularly for interventional radiology. A comprehensive database for mono-energetic photons between 4 and 150 keV and different field sizes was created for a 15 cm thick water phantom. Backscattered spectra were calculated with the PENELOPE Monte Carlo system, scoring track-length fluence differential in energy with negligible statistical uncertainty; using the Monte Carlo computed spectra, B factors and (mu(en)/rho)(omega), air were then calculated numerically for each energy. Weighted averaging procedures were subsequently used to convolve incident clinical spectra with mono-energetic data. The method was benchmarked against full Monte Carlo calculations of incident clinical spectra obtaining differences within 0.3-0.6%. The technique used enables the calculation of B and (mu(en)/rho)(w), air for any incident spectrum without further time-consuming Monte Carlo simulations. The adequacy of the extended dosimetry data to a broader range of clinical qualities than those currently available, while keeping consistency with existing data, was confirmed through detailed comparisons. Mono-energetic and spectra-averaged values were compared with published data, including those in ICRU Report 74 and IAEA TRS-457, finding average differences of 0.6%. Results are provided in comprehensive tables appropriated for clinical use. Additional qualities can easily be calculated using a designed GUI interface in conjunction with software to generate incident photon spectra.