36: A new model for computerized clinical electron beam dosimetry

This dose calculation model is based on separate treatment of primary electrons, primary bremsstrahlung generated in the regular photon and electron collimator system determining the composite beam, and the short-range contaminant photon and electron scatter arising from the lower parts of the standard electron applicator, in clinical electron beams. Experimentally determined primary electron scatter functions are used for the calculation of the primary electron dose. The primary bremsstrahlung is treated as an unflattened but otherwise regular X-ray beam. The contaminant components arising from the rim area of the regular electron collimator and from beam-shaping inserts are considered separately. The behavior of the in-air ionization profiles is described using the effective electron source position and effective electron source diameter. The model has been tested for several electron energies. 7 refs.; 3 figs