title: Portal films and their use in quality assurance--cranial irradiation.
authors.affiliation: Radiotherapy Department, St Bartholomew's Hospital, London.
authors.forename: C
authors.initials: C
authors.lastname: Walls
mesh_terms: D001921:Brain / Q000000981:diagnostic imaging*; D006801:Humans; D008577:Meningeal Neoplasms / Q000517:prevention & control*; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000517:prevention & control*; D011785:Quality Assurance, Health Care; D011859:Radiography / Q000706:statistics & numerical data; D011878:Radiotherapy / Q000592:standards*