Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA.
Health Phys. 2010 Jul;99(1):17-25. doi: 10.1097/HP.0b013e3181d3d828.
Skyshine radiation scattered in the atmosphere above a radiation therapy accelerator facility can result in measurable dose rates at locations near the facility on the ground and at roof level. A Reuter Stokes RSS-120 pressurized ion chamber was used to measure exposure rates in the vicinity of a Varian Trilogy Linear Accelerator at the Colorado State University Veterinary Medical Center. The linear accelerator was used to deliver bremsstrahlung photons from 6 MeV and 10 MeV electron beams with several combinations of field sizes and gantry angles. An equation for modeling skyshine radiation in the vicinity of medical accelerators was published by the National Council on Radiation Protection and Measurements in 2005. However, this model did not provide a good fit to the observed dose rates at ground level or on the roof. A more accurate method of estimating skyshine may be to measure the exposure rate of the radiation exiting the roof of the facility and to scale the results using the graphs presented in this paper.
在放射治疗加速器设施上方的大气中散射的天空辐射会导致设施附近地面和屋顶处的可测量剂量率。在科罗拉多州立大学兽医医学中心的瓦里安 Trilogy 线性加速器附近，使用 Reuter Stokes RSS-120 加压离子室来测量照射率。线性加速器用于从 6 MeV 和 10 MeV 电子束中输送韧致辐射光子，有几种射野大小和龙门架角度的组合。2005 年，国家辐射防护与测量委员会发表了一篇关于在医疗加速器附近模拟天空辐射的方程。然而，该模型对地面或屋顶处的观察到的剂量率拟合效果不佳。一种更准确的估算天空辐射的方法可能是测量离开设施屋顶的辐射的照射率，并使用本文中提供的图表对结果进行缩放。
