A measure of the capacity of a specific ionizing radiation to produce a specific biological effect, expressed relative to a reference radiation, such as radium gamma rays or 200-volt x-rays.比较生物效应：一个特定的游离辐射产生特定的生物效应的能量，用比较参考辐射量的反比，例如镭伽马射线或200伏X射线的办法表示出来