Deriving staff and public doses in a PET/CT facility from measured radiation levels using thermoluminescent dosimetry

The introduction of PET/CT at King Faisal Specialist Hospital and Research Centre for whole body and brain imaging has become favourable for diagnosis of cancer. There is no data available on the PET/CT dose to staff and members of the public for different activities of 18F [fluorodeoxyglucose (FDG)] and for longer patient holding time. The study aims to determine and evaluate staff and public doses by using thermoluminescent dosemeters monthly readings for a 7-month deployment period and by using direct measurements of dose rates at 30 cm and 1 m distances from the patients after injection. The whole body doses per procedure and per administered activity of 18F (FDG) were estimated. A dose map inside the PET/CT was generated to provide information of the dose levels in different locations. The Pearson correlation showed a strong correlation (r2 = 0.71) between the dose per activity and the number of patients. Optimisation of radiation protection of staff and members of the public was investigated and recommendations were given. (authors)