title: A sector-integration method for calculating the output factors of irregularly shaped electron fields.
abstract: An empirical model is presented that uses a sector-integration method for calculating the output factors of irregularly shaped electron fields. The sector-integration method accounts for changes in electron fluence, lateral scatter equilibrium, and scatter from the edge of a cutout shield. This method is tested for elliptical and rectangular fields with a ratio of the long-to-short axis as great as 4 to 1. Differences between measured and calculated values for output factors were less than +/- 1%. Comparisons were also carried out for a large number of cutout shields that were used in the clinic and similar levels of accuracy were obtained.
authors.affiliation: Battle Creek Health System, Department of Radiation Oncology, Michigan 49016, USA.
authors.forename: P A
authors.initials: PA
authors.lastname: Jursinic
authors.forename: R
authors.initials: R
authors.lastname: Mueller
mesh_terms: D055592:Biophysical Phenomena; D001703:Biophysics; D004583:Electrons / Q000627:therapeutic use*; D006801:Humans; D008962:Models, Theoretical; D010315:Particle Accelerators; D011880:Radiotherapy Planning, Computer-Assisted; D011882:Radiotherapy, High-Energy; D012542:Scattering, Radiation