The most modern method of increasing the depth dose is to use very hard radiation. After it became clear that increasing the voltage from 200 kV to 1000 kV (= 1 MV) gave little increase in the depth effect, one began paying attention to radiation of even higher energy. This energy is expressed in electron-volt (eV) and most of times the very hard radiations are characterized by the energy of their photons, which is several mega-electronvolts (MeV).
Unable to display preview. Download preview PDF.