Frota Marco A, Crispim Verginia R, Silva Ademir X, Kelecom Alphonse
Laboratório de Radiobiologia e Radiometria, Departamento de Biologia Geral, Universidade Federal Fluminense, Outeiro de São João Batista, s/n, Caixa Postal 100.436-24001-970 Niterói, RJ, Brazil.
Appl Radiat Isot. 2009 Jan;67(1):174-7. doi: 10.1016/j.apradiso.2008.08.012. Epub 2008 Sep 5.
This work aims to calculate the conversion coefficients from air kerma to ambient dose equivalent, H*(10)/K(air) for photon beams produced by linear accelerators, such as the Clinac-4, Clinac-6, Clinac-18 and Clinac-2500, after transmission through primary barriers of radiotherapy treatment rooms. Concrete walls of thickness 1.0, 1.5 and 2.0m were irradiated with 30cmx30cm primary beam spectra. The transmitted spectra were calculated to obtain the conversion coefficients for beams found in radiotherapy services. The calculations were done using the MCNP-4B Monte Carlo code. The results indicate the need to use a factor of about 1.20 to obtain the ambient dose equivalent for radiation surveys near primary barriers using instruments calibrated in air kerma.
本研究旨在计算直线加速器（如Clinac - 4、Clinac - 6、Clinac - 18和Clinac - 2500）产生的光子束在穿过放射治疗室的初级防护屏障后，从空气比释动能到周围剂量当量H*(10)/K(air)的转换系数。用30cm×30cm的初级射束光谱照射厚度为1.0、1.5和2.0m的混凝土墙。计算透射光谱以获得放射治疗服务中射束的转换系数。计算使用MCNP - 4B蒙特卡罗代码完成。结果表明，对于在空气比释动能中校准的仪器，在初级防护屏障附近进行辐射测量时，需要使用约1.20的系数来获得周围剂量当量。
