This study measured 99mTc-MDP bone scintigraphy radiation risks, as low-dose radiation exposure is a growing concern. Dosimeter measurements were taken at four positions (left lateral, right lateral, anterior, and posterior) around the patients at 30, 60, 100, and 200 cm at 0, 1.5, and 3 h. The highest dose rates were recorded from 51% of the patients, who emitted ≥ 25 µSv/h up to 49.00 µSv/h at the posterior location at a distance of 30 cm. Additionally, at the anterior location at a distance of 30 cm, 42% of patients emitted ≥ 25 µSv/h up to 38.00 µSv/h. Furthermore, at 1.5 h after the tracer injection, 7% of the dose rates exceeded 25 µSv/h. There was a significant reduction in mean dose rates for all positions as distance and time increased (p-value < 0.05). As a result, radiation levels decreased with increased distance and time as a result of radiation decay, biological clearance, and distance from the source. In addition, increasing the distance from the patient for all positions reduced the radiation dose, as was substantiated via exponential regression analysis. Additionally, after completing the bone scintigraphy, the patients' dose rates on discharge were within the current guidelines, and the mean radiation doses from 99mTc-MDP were below occupational limits. Thus, medical staff received less radiation than the recommended 25 μSv/h. On discharge and release to public areas, the patients' mean dose rates were as follows: 1.13 µSv/h for the left lateral position, 1.04 µSv/h for the right lateral, 1.39 µSv/h for the anterior, and 1.46 µSv/h for the posterior. This confirms that if an individual was continuously present in an unrestricted area, the dose from external sources would not exceed 20 µSv/h. Furthermore, the patients' radiation doses were below the public exposure limit on discharge.
Keywords: 99mTc; SPECT; bone scan; dose rate; low-dose radiation; nuclear medicine; occupational radiation exposure; radiation exposure; radiation protection; radiology.