Occupational Radiation Dosimetry Assessment Using an Automated Infusion Device for Positron-Emitting Radiotracers

Abstract

Handling and administration of radiopharmaceuticals are a key contributor to staff radiation dose. Shielded automated infusion devices potentially standardize and reduce radiation exposure during procedures. However, loading the devices adds incremental radiation exposure, which may mitigate dose savings. We measured radiation doses from the loading and use of an automated infusion device and compared these with those from manual injection of ¹⁸F radiotracers. Methods: Adult patients were administered ¹⁸F-FDG or ¹⁸F-FLT before 3-dimensional PET whole-body or brain imaging, respectively. Radioactivity amounts from manual injections performed with protective syringe shields and vial holders were measured by a standard dose calibrator before and after injection. Automated infusions were performed using the shielded infusion device. Staff wore electronic dosimeters at the wrist and trunk. Electronic dosimeters were also worn while multidose ¹⁸F-FDG vials were loaded and unloaded. For each task, background radiation was determined and subtracted from the electronic dosimeter values. Results: Twenty-seven manually injected unit doses yielded a mean administered dose to patients of 480.7 ± 66.2 MBq (12.99 ± 1.79 mCi), compared with 431.9 ± 22.7 MBq (11.67 ± 0.61 mCi) in 34 automated injections. The mean difference was statistically significant. To control for this difference, results were expressed as a standardized dose per unit of activity. With the automated infusion device, the mean extremity dose per injection was 0.003 ± 0.002 μSv/MBq, compared with 0.026 ± 0.017 μSv/MBq with manual injections. Mean body dose per procedure with automated infusion was 0.001 μSv/MBq, versus 0.011 μSv/MBq with manual injection (P < 0.001). The changing of bulk ¹⁸F-FDG vials in 37 procedures added a mean dose per vial change of 0.89 ± 1.3 μSv to the extremities and 0.47 ± 2.0 μSv to the body. Conclusion: The use of a shielded automatic infusion device in a clinical PET setting resulted in an approximately 10-fold decrease in staff extremity and body doses during the administration of ¹⁸F-labeled radiopharmaceuticals. Loading and unloading bulk vials of radiotracer did not significantly offset these dose savings.