Stability of Calibration Coefficient of Type Ionization Chambers at ⁶⁰Co Teletherapy Beam in Malaysia

Full-text:Absorbed dose-to-water (DW) calibration is critical to the medical community to achieve the accuracy of the dose delivered to tumors during radiotherapy treatment. Therefore, the IAEA recommended annual calibration of ionization chambers with a calibration coefficient (ND,W) that must be within the acceptable range of ± 1.5%. In this study, three types ion chambers, used in most of the radiotherapy centers (RCs) have been calibrating at SSDL Laboratory of the Malaysian Nuclear Agency for seven years. The mean (μ) of the ND,W deviation together with its standard error (SE) of these chambers was calculated to measure stability of NDW. It was found that the μ±SE value lies within the acceptable limits. Thus, this indicates that the calibrated ion chambers are safely to be used for radiotherapy treatment due to the stabilization of ND,W. (author)