Personnel radiation dose considerations in the use of an integrated PET–CT scanner for radiotherapy treatment planning

¹ Medical Physics Agency, Royal Group of Hospitals, Grosvenor Road, and 2Radiation Oncology and 3Medical Physics Agency, Northern Ireland Cancer Centre, Belfast City Hospital, Belfast

	Abstract

The acquisition of radiotherapy planning scans on positron emission tomography (PET)–CT scanners requires the involvement of radiotherapy radiographers. This study assessed the radiation dose received by these radiographers during this process. Radiotherapy planning 18F-fluorodeoxyglucose (¹⁸F-FDG) PET–CT scans were acquired for 28 non-small cell lung cancer patients. In order to minimise the radiation dose received, a two-stage process was used in which the most time-consuming part of the set-up was performed before the patient received their ¹⁸F-FDG injection. Throughout this process, the radiotherapy radiographers wore electronic personal dosemeters and recorded the doses received at different stages of the process. The mean total radiation dose received by a radiotherapy radiographer was 5.1±2.6 µSv per patient. The use of the two-stage process reduced the time spent in close proximity to the patient by approximately a factor of four. The two-stage process was effective in keeping radiation dose to a minimum. The use of a pre-injection set-up session reduces the radiation dose to the radiotherapy radiographers caused by their involvement in PET–CT radiotherapy treatment planning scans by approximately a factor of three.