Assessment of Ionization Chambers Performance Using Standard Source Co60

Abstract

Understanding quality control and calibration of ionization chambers which are used as dosimeters in department of radiotherapy at RICK by using standard sources of cobalt 60 as well as acquiring necessary and sufficient training are considered as very important for clinical dosimetry. The aims of this study were:8 1- to assess the performance of the Ionization chambers using standard sources co60, 2- Determine the efficiency and accuracy of Ionization Chambers, 3-Compare between the responses of different ionization chambers at RICK with reference ion chamber, 4- Create a conversion factors of different type of ionization chambers by using reference chamber. Three co60 sources with different activities and water phantom and slap phantom were used to achieve a high evaluation of ion chambers, accuracy and efficiency. The total uncertainty in the determination of the dose to water during calculation of the beam was found to be less than 1% and this magnitude within the accepted limits of recommendation of the IAEA protocol 2%. All ion chambers used in this study showed good precision (reproducibility), linearity and accuracy, except one ion chamber which is FC65-G with uncertainty of which is out of limit 7%.