Quantities and Units in Radiation Protection

Interaction of all kinds of radiation with matter ultimately results in the transfer of energy, through the processes of ionization and excitation. Quantifying the transfer of energy is important to the two most fundamental areas of radiation protection: radiation dosimetry and radiation instrumentation. Understanding these two areas is essential to the practice of health physics in almost every practical application. We have already studied the forms of these interactions. Now we discuss quantitative measures of these interactions. As discussed in Chapter 2, it is important to understand the distinction between a quantity (the parameter being measured) and a unit (the measure of the quantity). For example, velocity is the quantity that describes the time rate of motion of an object, and an example of the units that describe velocity is kilometers per hour (km/h).