The current status and issues regarding positron dosimetry in nuclear medicine are summarized. The suitability of the United Kingdom Health Security Agency extremity and eye beta-gamma personal thermoluminescence dosemeters are then considered. Monte Carlo modelling is performed to determine their responses and derive sets of calibration factors, along with H p(0.07) and H p(3) conversion coefficients, for carbon-11, nitrogen-13, oxygen-15, fluorine-18 and gallium-68 sources, which are commonly used in positron emission tomography (PET) computed tomography; data for these isotopes is assumed extrapolatable to other positron sources. It is found that the dosemeters are adequate for assessing exposures to PET radionuclides, even if their routine calibrations to caesium-137 were maintained. An idealized set of measurements representing gallium-68 exposure scenarios is then described, including reproducible mock-ups of individuals manipulating vials and syringes. Finally, a short case-study is presented that explores occupational doses during routine clinical use of gallium-68. The extremity dosemeter results demonstrated significant variations dependent upon the exposure conditions, with some seen to be comparatively large; whole-body and eye dose rates per activity were found to be lower. The importance of routine dose monitoring of workers is emphasized, with the need for a longer-termed follow-up study demonstrated.
|Journal||Journal of Radiological Protection|
|Publication status||Published - Sept 2022|
Bibliographical noteFunding Information:
The authors thank staff and colleagues at St James’s Hospital, Dublin, and Royal Free London NHS Foundation Trust, London, for their invaluable participation in this research, and are grateful to both organizations for their overall support of the project. We also thank UKHSA’s Approved Personal Dosimetry Service (PDS) for supplying and processing the dosemeters.
© 2022 Society for Radiological Protection. Published on behalf of SRP by IOP Publishing Limited. All rights reserved.
- Monte Carlo
- medical dosimetry
- occupational exposures
- personal dosimetry