title: An expression for backscatter factors for orthovoltage x-rays.
abstract: Backscatter factors for orthovoltage x-ray beams are fitted with the expression BSF = 1 + ms/(s + n), where s is field size and m and n are adjustable parameters. The accuracy is better than 0.5%. Good results were also obtained for Cs-137 gamma rays at depth 0.12 cm and Co-60 gamma rays at depth 0.5 cm using the same expression, which failed, however, for peak scatter factors at high x-ray energies.
authors.affiliation: Department of Radiation Oncology, University of Pennsylvania, Philadelphia 19104-4283, USA. xiao@xrt.upenn.edu
authors.forename: Y
authors.initials: Y
authors.lastname: Xiao
authors.forename: B
authors.initials: B
authors.lastname: Bjärngard
mesh_terms: D000465:Algorithms; D002588:Cesium Radioisotopes; D005720:Gamma Rays; D019047:Phantoms, Imaging; D017785:Photons; D011829:Radiation Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D011882:Radiotherapy, High-Energy; D012542:Scattering, Radiation; D014867:Water; D014965:X-Rays
chemical_list: D002588:Cesium Radioisotopes; D014867:Water