title: Characteristics of contamination electrons in high energy photon beams.
abstract: A simple method to estimate the contribution of contaminating electrons to the dose, and to evaluate their dosimetric characteristics is proposed. The method is based on a normalisation of the tissue--maximum ratio curves to a constant primary photon fluence. The contribution of the contaminating electrons to the dose is calculated by subtracting the dose relative to a small field from the dose relative to the field under consideration. The method includes the determination of the mean energy, the linear apparent attenuation coefficient, the 50% range and the maximum range of the contaminating electrons. The extrapolated surface dose normalised to a constant primary photon fluence has been found to be constant for a constant collimator opening whatever may be the source distance.
authors.affiliation: Physics Department, Insitut Gustabe Roussy, Villejuif, France.
authors.forename: H
authors.initials: H
authors.lastname: Beauvais
authors.forename: A
authors.initials: A
authors.lastname: Bridier
authors.forename: A
authors.initials: A
authors.lastname: Dutreix
mesh_terms: D000042:Absorption; D004583:Electrons; D004735:Energy Transfer; D006801:Humans; D008954:Models, Biological; D008961:Models, Structural; D008962:Models, Theoretical; D010315:Particle Accelerators; D017785:Photons; D011879:Radiotherapy Dosage; D011882:Radiotherapy, High-Energy; D012542:Scattering, Radiation; D012867:Skin / Q000528:radiation effects*; D014965:X-Rays