Aim: It was the aim of the study to assess the additional radiation exposure to patients, attendants and nurses by patients who are undergoing nuclear medicine investigations (myocardial scintigraphy) with 201TL-chloride (201TL-CL).
Method: In 16 cases the dose rates at 0.5 1 and 2 m distance from patients were measured at 0.5, 1.5, 3-4 and 24, in some cases until 370 h after administration of 100 +/- 10 MBq 201TL-CL. From the time courses of the dose rates around the patients the possible radiation exposure of other persons were estimated.
Results: The initial values of the dose rate were 3.82 microSv/h at 0.5 m, 1.18 microSv/h at 1 m and 0.30 microSv/h at 2 m distance from the patients respectively. The dose rates were decreasing following a monoexponential course with an effective half-life of 60 h. The maximum doses to other persons at 1 m distance from the patients were determined by considering three scenarios. The values were 13 microSv in the waiting room, 26 microSv for nurses, working in the ward and 105 microSv for persons living in the same house hold
Conclusion: Even at very restrictive assumptions the closes were far below the maximum permissible dose to non-radiation workers see by radiation protection regulations (1.5 mSv per year).