On the Definition of Sievert and Its SI Unit

The sievert (symbol: Sv) is the special name for the International System of Units (SI) of equivalent dose, which is defined as 1 Sv = 1 J kg -1 . Depending on the radiation type, however, an inconsistency occurs in which the same energy imparted per unit mass (e.g., 1 J kg -1 ) will result in different equivalent doses (e.g., 1 Sv for x-rays and 20 Sv for alpha particles). This short communication discusses the definition of equivalent dose and suggests to redefine sievert as a measure of the equivalent biological effect produced by 1 J kg -1 of absorbed dose.