Avila-Rodriguez Miguel A, DeLuca Paul M, Bohm Tim D
Department of Medical Physics, University of Wisconsin-Madison, 1530 MSC, 1300 University Avenue, Madison, WI 53706-1532, USA.
Radiat Prot Dosimetry. 2005;116(1-4 Pt 2):547-52. doi: 10.1093/rpd/nci227.
The Monte Carlo N-particle code MCNP version 4C3 was used to investigate the backscattering and transmission of high-energy photons in concrete, iron and lead at deep penetration. A typical bremsstrahlung beam from a 24 MV linac was used, and the transmission up to 15 mean-free paths was studied. Broad beam slab geometry was used. Estimates of the transmission in terms of absorbed dose to tissue ratio and air kerma ratio were performed for the primary and secondary components of the transmitted beam in the three materials. The tissue dose and air kerma buildup factors were calculated and fitted to Berger's equation. Finally, the differential dose albedo values for common reflected angles were determined.
使用蒙特卡罗N粒子代码MCNP版本4C3来研究高能光子在混凝土、铁和铅中的深层穿透时的反向散射和透射。使用了来自24兆伏直线加速器的典型轫致辐射束，并研究了高达15个平均自由程的透射情况。采用宽束平板几何结构。针对三种材料中透射束的初级和次级成分，以组织吸收剂量比和空气比释动能比的形式进行了透射估计。计算了组织剂量和空气比释动能积累因子，并将其拟合到伯杰方程。最后，确定了常见反射角的微分剂量反照率值。
