Workflow and radiation safety implications of (18)F-FDG PET/CT scans for radiotherapy planning

The use of (18)F-FDG PET/CT for radiotherapy planning may lead to better tumor volume definition. Reproduction of the patient's position when setting up an (18)F-FDG PET/CT scan for radiotherapy planning is more accurate if a radiation therapist is involved. The aim of this study was to compare setup time and staff radiation dose between radiation therapists and nuclear medicine technologists.

Forty patients with newly diagnosed head and neck or non-small cell lung cancer were prospectively recruited into this study. Twenty patients (10 with head and neck cancer and 10 with non-small cell lung cancer) underwent (18)F-FDG PET/CT for radiotherapy planning, and 20 patients (10 with head and neck cancer and 10 with non-small cell lung cancer) underwent (18)F-FDG PET/CT for staging. Setup time was measured, and a radiation monitor recorded the highest dose (μSv/h) to staff during setup.

For radiation therapists, the mean setup time for a lung scan (in min:s) was 5:22 ± 2:11 (range, 2:22-9:23), with a highest dose of 4.94 ± 3.78 μSv (range, 2.02-15.23 μSv), and the mean setup time for a head and neck scan was 4:49 ± 1:45 (range, 2:03-8:21), with a highest dose of 3.93 ± 1.45 μSv (range, 1.19-6.83 μSv). For nuclear medicine technologists, the mean setup time for a lung scan was 1:58 ± 0:24 (range, 1:17-2:38), with a highest dose of 3.30 ± 1.28 μSv (range, 1.92-5.47 μSv), and the mean setup time for a head and neck scan was 2:12 ± 0:38 (range, 1:03-3:16), with a highest dose of 3.10 ± 1.78 μSv (range, 1.56-7.49 μSv).

This study showed that setup time and operator radiation dose were greater for radiation therapists setting up planning (18)F-FDG PET/CT scans than for nuclear medicine technologists setting up routine (18)F-FDG PET/CT scans. These results have implications for scheduling of radiotherapy planning PET/CT; however, the additional radiation dose was not considered to be significant.