Optimizing Radiation Protection in PET/CT Examinations: Reducing Occupational Exposure During Patient Positioning

Abstract

Objectives The objective of this study was to evaluate the occupational radiation exposure of healthcare workers during positron emission tomography (PET)/CT examinations, focusing on patient positioning and assessing the effectiveness of different radiation protection measures. Methods Thirteen medical workers (physicians, radiological technologists, and nurses) performed PET/CT examinations on 86 patients at a major Japanese hospital from June to August 2019. Occupational doses were measured using a real-time semiconductor dosimeter: RaySafe i2 (Unfors RaySafe, Billdal, Sweden), recording the 1 cm dose equivalent (Hp(10)). Exposure during various tasks was assessed, and radiation protection measures were evaluated, including increasing the number of personnel during patient positioning, using a protective screen (3.0 mm lead equivalent; Kuraray Trading Co., Ltd., Osaka, Japan), and implementing remote patient positioning via the PET/CT operator console. Results Patient positioning and discharge (task 4) resulted in the highest occupational exposure, with a median Hp(10) of 0.66 μSv per event (interquartile range (IQR): 0.54-0.71 μSv). Increasing the number of staff during task 4 did not significantly reduce occupational dose (p=0.725). Using a protective screen reduced the median Hp(10) to 0.58 μSv per event (IQR: 0.51-0.80 μSv). Remote positioning via the operator console further reduced it to 0.49 μSv per event (IQR: 0.35-0.62 μSv), achieving a significant dose-reduction (p=0.016). The dose reduction rates were 23.7% for the protective screen and 35.5% for the operator console method. Conclusions Patient positioning is the primary source of occupational radiation exposure during PET/CT examinations. Remote positioning via the operator console significantly reduces occupational exposure and working time compared to other methods, providing an effective and cost-efficient radiation protection strategy that aligns with the As Low As Reasonably Practicable (ALARP) principle. Advances in knowledge This study demonstrates that remote patient positioning via the operator console is an effective, easily implementable radiation protection measure that enhances operational efficiency without additional costs, representing a valuable advancement in occupational safety during PET/CT examinations.

Keywords: 1 cm dose equivalent; 18f-fdg; alarp; occupational exposure; patient positioning; pet/ct; radiation protection; real-time semiconductor dosimeter.

Figure 1. Schematic map of the facility

1. medication room; 2. preparation room; 3. resting room; 4, toilet; 5. corridor; 6. PET/CT room; 7. imaging console room; 8, disposal room. Task 1 - radiopharmaceutical preparation and isotope handling; task 2 - radiopharmaceutical administration; task 3 - patient care in the resting room (psychologically restlessness patients, patients who needed walking assistance (due to a risk of fall), patients who needed to be transferred to a wheelchair, etc.); and task 4 - patient positioning and discharge. Each task was performed by a radiological technologist (tasks 1 and 4), a physician (task 2), and a nurse (task 3). PET - positron emission tomography

Figure 2. The i2 dosimeter attachment position is shown

Hp(10) were measured using a real-time semiconductor dosimeter (RaySafe i2: Unfors RaySafe, Billdal, Sweden).The i2 dosimeter attachment position is shown.

Figure 3. Position of the protective screen

This figure illustrates the placement of the 3.0 mm-Pb protective screen in the PET/CT examination room. The screen is strategically positioned to minimize scattered radiation exposure to healthcare workers, particularly during prolonged procedures.