[Consideration of inhomogeneities in irradiation planning. 3. Influence of inhomogeneities on the shape of the depth dose curve in water with electronic radiation of different energies (author's transl)].

For electron beams the shift of the depth dose curve in water produced by an inhomogeneity with density rho2 and thickness d is to be calculated from Vcalc-d(rho1 -1). Because of additional energy losses by bremsstrahl production, this calculable value Vcalc has to be corrected by means of a factor K to be found experimentally. In the case of larger atomic numbers (metallic plate), and most intensely in the lower energy range from 10 to 20 MeV the loss of dosage on account of inhomogeneities is particularly high due to elastic scattering of electrons (e.g. 86% by a 4.5 mm metallic plate with 10 MeV electronic radiation).