There should be no confusion about the level of radiation an individual receives; unfortunately, there is. The International Commission on Radiological Units and Measurements (ICRU) introduced the current framework of radiological quantities and units in the early 1980s. The major changes from the previous commonly used units (conventional units) were consistency with the International System of Units, in that the unit for radiation absorbed dose is the unit ratio of fundamental units (i.e., 1 Gy = 1 joule/kg) rather than some multiplicative factor of the ratio, and a unit for radiation exposure was not defined.

Unfortunately, a fundamental problem with conventional units was not addressed. The same unit was assigned to two different radiological quantities: radiation equivalent dose and radiation effective dose. I have been teaching radiologists and radiological technologists and working with these groups and...