The stopping powers and ranges of hydrogen and helium ions

ICRU publications form the legal and scientific backbone of medical physics. The ICRU publishes definitions, acceptable unit notations, procedures for measurement and applications, and physical data as directed by the International Commission in Radiological Protection (ICRP). Each of the ICRU publications are created using special ad-hoc commissions of international scientific experts. Some of these publications become the world-standard in not only medical physics, but for all physics, for example ICRU-37, `Stopping Powers for Electrons and Positrons' (1984), is still the most cited source for electron stopping powers. The newest ICRU publication on stopping powers (1994), ICRU-49, will be reviewed with emphasis on how the tables were derived and their accuracy.