Build-up curves have been measured for clinical photon beams with energies from 1.2 to 25 MV. The position of the depth of maximum dose and the percentage depth dose in the build-up region has been found to depend sensitively upon field size for some machines. These effects are interpreted in terms of an electron component of the radiation field. The significance of the observations for megavoltage radiation therapy is discussed.
|Number of pages||5|
|State||Published - Jan 1 1980|