Background: Nearly all radiation safety courses teach that scatter radiation around the x-ray table falls with the inverse of the distance from the imaging site. Humans, however, are complex x-ray reflectors and the application of the inverse square law to clinical imaging is only assumed. Methods: We measured scatter radiation at two positions where staff commonly stand around the x-ray table. Using an anthropomorphic human phantom, human and pig cadavers, and a glass sphere, we measured scatter radiation levels in each position, and then 2- and 3-fold the distance from the imaging site. We compared the measured scatter radiation to that predicted by the common inverse square law and a more detailed geometric inverse square law. Results: In all but the glass sphere, scatter radiation was much higher below the table (68-74% of all scatter radiation, depending on model and position) than above the table (26-32% of scatter radiation, p < 0.01). Scatter radiation fell with increasing distance from the table, but above the table both inverse square laws significantly over-estimated the benefit of stepping back (19-93% overestimation by geometric inverse square law at 2-fold distance, 14-46% at 3-fold). In addition, a pelvis in the phantom appeared to cause significant scatter radiation field anomalies at the angiographer position. Conclusion: Stepping back from the table does not reduce scatter radiation levels as much as the inverse square law predicts. The geometric inverse square law best predicts the reduction in scatter radiation below the table, but above the table it too overestimates the benefit of stepping back. The irregularity of the scatter radiation field should be taken into account by scatter radiation shielding systems.

中文翻译：

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从 X 射线台后退对操作员辐射暴露的影响。

背景：几乎所有辐射安全课程都教导 X 射线床周围的散射辐射与距成像部位的距离成反比。然而，人类是复杂的 X 射线反射体，平方反比定律在临床成像中的应用只是假设的。方法：我们测量了工作人员通常站在 X 射线床周围的两个位置的散射辐射。使用拟人化的人体模型、人和猪尸体以及玻璃球，我们测量了每个位置的散射辐射水平，然后测量了距成像部位距离的 2 倍和 3 倍。我们将测量的散射辐射与常见的平方反比定律和更详细的几何平方反比定律预测的散射辐射进行了比较。结果：除玻璃球外，在所有球体中，桌子下方的散射辐射（所有散射辐射的 68-74%，具体取决于型号和位置）远高于桌子上方（散射辐射的 26-32%，p < 0.01） 。散射辐射随着距桌子距离的增加而下降，但在桌子上方，两个平方反比定律都显着高估了后退的好处（几何反平方定律在 2 倍距离处高估了 19-93%，在 3 倍距离处高估了 14-46%） -折叠）。此外，模型中的骨盆似乎会在血管造影师位置引起明显的散射辐射场异常。结论：从表中退后一步并不会像平方反比定律预测的那样降低散射辐射水平。几何平方反比定律最好地预测了桌子下方散射辐射的减少，但在桌子上方它也高估了后退的好处。散射辐射屏蔽系统应考虑散射辐射场的不规则性。