Integral Doses at 200 kV and 8 MeV

Calculated values of integral doses delivered during radiotherapy at 8 MeV and with radiation of H.V.L. = 2 mm of Cu are presented. These values have been checked experimentally. Meredith and Neary's method is found to give reliable values of integral dose at H.V.L. = 2 mm of Cu. The experimental measurements were made with a celluloid model of the human body, the model being composed entirely of ionization chambers. A description of the model is given, together with an analysis of the derivation of integral doses from measured ionization currents. The integral doses delivered during typical treatments at the two qualities are compared. It is found that in practice integral doses are not always greatly reduced at 8 MeV, owing to the differing field arrangements used.