A comprehensive assessment of radiation protection practices in dental clinics for patients administered 99mTc MDP undergoing bone scintigraphy

Abstract

Objective: This study aimed to determine the potential radiation doses to which dentists may be exposed when examining or performing interventional procedures on patients who have undergone technetium-99m methylene diphosphonate (⁹⁹ᵐTc-MDP) bone scintigraphy, primarily performed for the evaluation of bone malignancies. In addition, it sought to identify appropriate radiation protection measures from the perspective of dental practitioners. Materials and Methods: A total of 53 patients who underwent bone scintigraphy were included in this study. Each patient received an average of 925 megabecquerels (MBq) of ⁹⁹ᵐTc-MDP as a radiopharmaceutical. Two hours after administration, bone scintigraphy imaging was performed. Between 0.5 and 3 hours after imaging, radiation dose rate measurements were obtained from the head–neck, thoracic, and abdominopelvic regions using a radiation detector positioned at distances of 5 cm, 15 cm, 30 cm, 60 cm, and 100 cm. Results: The mean dose rates measured from the thoracic region at 5 cm, 15 cm, 30 cm, 60 cm, and 100 cm were 144.3 ± 36.9, 107.2 ± 16.9, 73.5 ± 13.8, 42.7 ± 10.0, and 12.5 ± 8.7 µSv/h, respectively. It was estimated that the daily exposure dose to a dentist would be below 4 µSv after approximately 10.4 hours of patient contact. Conclusion: If a patient who has undergone bone scintigraphy visits a dentist for examination or treatment 3 hours after imaging, the dentist’s radiation exposure would remain below the annual dose limit of 1 mSv. However, it was also determined that the 4 µSv/day exposure threshold could be reached after approximately 10.4 hours of close contact.