title: An equivalent-square formula for head-scatter factors.
abstract: A simple formula is evaluated for calculating the equivalent square collimator setting that gives the same headscatter factor as a given rectangular field. The expression requires that one parameter is determined experimentally. It is found that one single value of this parameter can be used for the six x-ray beams studied (two accelerators, two energies, with and without wedge).
authors.affiliation: Department of Radiation Oncology, Roger Williams Cancer Center, Brown University Providence, Rhode Island 02908.
authors.forename: P
authors.initials: P
authors.lastname: Vadash
authors.forename: B
authors.initials: B
authors.lastname: Bjärngard
mesh_terms: D006801:Humans; D009369:Neoplasms / Q000532:radiotherapy*; D010315:Particle Accelerators; D011882:Radiotherapy, High-Energy; D012542:Scattering, Radiation