title: Long-term use of an isotope check source for verification of ion chamber calibration.
abstract: A radioactive check source is recommended for operational and constancy checks of dosimetry systems used for the calibration of therapeutic x-ray generators, including linear accelerators. Eight years of data have been analyzed for two ion chambers (and their associated electrometers) irradiated at fixed geometry in such a device. These dosimetry systems have also been calibrated every 2 years at a single Accredited Dosimetry Calibration Laboratory. Our analysis suggests that when a check source is used, and the results are consistent, the interval between formal calibrations can be lengthened.
authors.affiliation: Division of Radiation Oncology, NYU Medical Center, New York 10016.
authors.forename: R J
authors.initials: RJ
authors.lastname: Barish
authors.forename: I A
authors.initials: IA
authors.lastname: Lerch
mesh_terms: D006801:Humans; D010315:Particle Accelerators / Q000592:standards; D011785:Quality Assurance, Health Care; D011835:Radiation Protection / Q000592:standards*; D011878:Radiotherapy / Q000295:instrumentation*; D013324:Strontium
chemical_list: D013324:Strontium