title: An equivalent square method for irregular photon fields.
abstract: A quick formula is proposed for calculating equivalent squares of irregularly shaped photon fields. No complex calculations are required. Three different energies (60Co; 6 MV and 18 MV x-rays) were investigated. Comparison with results utilizing the Clarkson technique (60Co) and with experimental measurements (6 MV and 18 MV x-rays) indicates that the method is accettable in a wide variety of clinical situations. The applied procedure introduces an indetermination lower than 4%, with maximum absolute percentage errors of 3%, 2.7%, and 3.6% for 6 MV, 18 MV, and 60Co photon fields respectively.
authors.affiliation: Department of Medical Physics, Ospedale S. Anna, Como, Italy.
authors.forename: A F
authors.initials: AF
authors.lastname: Monti
authors.forename: A
authors.initials: A
authors.lastname: Ostinelli
authors.forename: M
authors.initials: M
authors.lastname: Frigerio
authors.forename: S
authors.initials: S
authors.lastname: Gelosa
mesh_terms: D000465:Algorithms; D003037:Cobalt Radioisotopes / Q000008:administration & dosage / Q000627:therapeutic use; D006801:Humans; D017785:Photons; D011835:Radiation Protection / Q000295:instrumentation; D011879:Radiotherapy Dosage; D011882:Radiotherapy, High-Energy
chemical_list: D003037:Cobalt Radioisotopes