Evaluation of occupational exposure associated with PET/CT and nuclear medicine procedures

Objectives Nuclear medicine technologists receive occupational radiation exposure from a variety of imaging procedures and activities. Our aim was to evaluate the occupational exposure associated with specific patient-related tasks in the context of PET/CT imaging.

Methods Technologists carried an additional optically-stimulated luminescence dosimeter while solely performing PET/CT-related tasks over an 8-month period. These tasks were categorized into tracer injection and patient handling post injection. Patient handling encompasses scan preparation and patient positioning on and off the scanner. Technologists used designated stopwatches to record the time spent performing tasks on 856 PET/CT patients. The number of PET/CT tasks performed was also recorded for each technologist.

Results Technologists received significantly more of their exposure (p=0.0001) from PET/CT-related procedures (mean=76%) than from general nuclear medicine-related tasks (mean=24%). Of the various PET/CT tasks evaluated, the average injection time had a positive correlation with exposure (Spearman correlation coefficient=0.7, p=0.04), as did the average time for patient handling post injection (Spearman correlation coefficient=0.7, p=0.04). However, these tests were no longer significant after we adjusted for multiplicity by Bonferroni correction. There is also no significant association between exposure and the number of scans performed, or between cumulative time taken for each task (number of patients x average time) and exposure after adjusting for multiplicity.

Conclusions The majority of occupational exposure in our oncology-based practice comes from PET/CT-related procedures. PET tracer injection time was identified as the single task that required the most time to execute. Technologists should continue to aim at optimizing tracer injection techniques and efficiency as to further decrease exposure to a level that is as low as reasonably achievable