title: Wedge factor dependence with depth and field size for fast neutron beams.
abstract: The dependence of the wedge factors (WFs) on field size (FS) and depth for a fast neutron beam has been investigated. In a previous study (Popescu et al 1999 Med. Phys. 26 541), a method was presented that allows a simple and accurate way of calculating the wedge-factor dependence on FS and depth in the case of a photon beam. The validity of a similar approach is tested in the present study for neutron beam dosimetry. The clinical neutron therapy system at the University of Washington (UW) has a flattening filter assembly consisting of two filters: a small field filter and a large field filter. Despite this complication, the approach presented in Popescu et al (1999 Med. Phys. 26 541) can be used to describe the WF dependence on FS and depth (d).
authors.affiliation: Department of Radiation Oncology, University of Washington Medical Center, 1959 N E Pacific Street, Seattle, WA 98195-6043, USA.
authors.forename: Alina
authors.initials: A
authors.lastname: Popescu
authors.forename: Ruedi
authors.initials: R
authors.lastname: Risler
mesh_terms: D002138:Calibration; D019544:Equipment Failure Analysis; D005214:Fast Neutrons / Q000627:therapeutic use*; D006801:Humans; D017247:Neutron Capture Therapy / Q000295:instrumentation* / Q000379:methods*; D011874:Radiometry / Q000295:instrumentation* / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation* / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity