Lens dose and radiogenic risk from 99mTc nuclear medicine examinations

Evaluation has been made of the radiogenic risks to patients and personnel during Tc-99m diagnostic nuclear medicine examinations. A highly sensitive form of thermoluminescent dosimeter, type TLD-GR200A (LiF: Mg, Cu, P), was used to quantify occupational exposure. Ambient exposure rates and patient doses were also assessed using a survey meter and knowledge of the administered activity respectively. For bone, renal and thyroid scans, the mean Tc-99m administered activities were 925.0 MBq, 148.0 MBq and 166.5 MBq respectively. The staff annual dose was estimated to be 11.2 mSv and eye lens dose equivalent was 2.2 mSv. The dose values are greater in comparison with other studies but with the current workload and practices they remain within the annual occupational dose limit.