title: Photon spectrum and absorbed dose in brain tumor.
abstract: Using Monte Carlo methods a BOMAB phantom inside a treatment hall with a brain tumor nearby the pituitary gland was treated with photons produced by a Varian 6MV linac. The photon spectrum and the absorbed dose were calculated in the tumor, pituitary gland and the head. The treatment beam was collimated to illuminate only the tumor volume; however photons were noticed in the gland. Photon fluence reaching the tumor is and 15.7 times larger than the fluence in the pituitary gland, on the other hand the absorbed dose in the tumor is 37.1 times larger than the dose in the gland because photons that reach the pituitary gland are scattered, by the head and the tumor, through Compton effect.
authors.affiliation: Unidad Académica de Estudios Nucleares de la Universidad Autónoma de Zacatecas, Calle Ciprés 10, Fracc. La Peñuela 98068, Zacatecas, Zacatecas México. Electronic address: fermineutron@yahoo.com.
authors.forename: Hector Rene
authors.initials: HR
authors.lastname: Vega-Carrillo
authors.affiliation: General Electric Healthcare, Antonio Dovali Jaime 70, Torre A 3er Piso, Col. Santa Fe 01210, México D.F.
authors.forename: Angeles
authors.initials: A
authors.lastname: Silva-Sanchez
authors.affiliation: Centro de Investigación en Ciencia y Tecnología Avanzada - IPN, Av. Legaria 694, C.P. 11500, México D.F.
authors.forename: Teodoro
authors.initials: T
authors.lastname: Rivera-Montalvo
mesh_terms: D065638:Absorption, Radiation; D001921:Brain / Q000503:physiopathology / Q000528:radiation effects; D001932:Brain Neoplasms / Q000503:physiopathology* / Q000532:radiotherapy*; D003198:Computer Simulation; D016371:Cranial Irradiation / Q000379:methods*; D006801:Humans; D008954:Models, Biological; D015233:Models, Statistical; D009010:Monte Carlo Method; D017785:Photons / Q000627:therapeutic use*; D010902:Pituitary Gland / Q000503:physiopathology* / Q000528:radiation effects; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods; D012542:Scattering, Radiation
keywords: Absorbed dose; LINAC; Monte Carlo; Phantom; Radiotherapy; Tumor