A survey of the practice and management of radiotherapy linear accelerator quality control in the UK

The objective of this study was to determine current radiotherapy linear accelerator quality control (QC) practice in the UK, as a comparative benchmark and indicator of development needs, and to raise awareness of QC as a key performance indicator. All UK radiotherapy centres were invited to complete an online questionnaire regarding their local QC processes, and submit their QC schedules. The range of QC tests, frequency of measurements and acceptable tolerances in use across the UK were analysed, and consensus and range statistics determined. 72% of the UK's 62 radiotherapy centres completed the questionnaire and 40% provided their QC schedules. 60 separate QC tests were identified from the returned schedules. There was a large variation in the total time devoted to QC between centres: interquartile range from 13 to 26 h per linear accelerator per month. There has been a move from weekly to monthly testing of output calibration in the last decade, with reliance on daily constancy testing equipment. 33% of centres thought their schedules were in need of an update and only 30% used risk-assessment approaches to determine local QC schedule content. Less than 30% of centres regularly complete all planned QC tests each month, although 96% achieve over 80% of tests. A comprehensive "snapshot" of linear accelerator QC testing practice in the UK has been collated, which demonstrates reasonable agreement between centres in their stated QC test frequencies. However, intelligent design of QC schedules and management is necessary to ensure efficiency and appropriateness.