The lifetime of a linac monitor unit ion chamber.

This study is the first to report the clinical lifetime of Varian Kapton sealed ion chambers as a retrospective review. The data have been analyzed using ion chamber gain values, daily quality assurance results,monthly quality assurance results, and delivered treatment field data were analyzed to comprehensively review trends. The data show the average lifetimes of the ion chambers from our institution, so other physicists can prepare for replacement. Additionally, we share our experience in performing quality assurance tests to calibrate and validate the radiation beam after ion chamber replacement. [ABSTRACT FROM AUTHOR]