RADIATION EXPOSURE AROUND PATIENTS AFTER TL-201-MYOCARDIAL SCINTIGRAPHY

Aim: It was the aim of the study to assess the additional radiation ex posure to patients, attendents and nurses by patients who are undergoi ng nuclear medicine investigations (myocardial scintigraphy) with (TI) -T-201-chloride ((TI)-T-201-CI). 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 (TI)-T-201-CI. From the time courses of the dose rates around the pat ients the possible radiation exposure of other persons were estimated. Results: The initial values of the dose rate were 3.82 mu Sv/h at 0.5 m, 1.18 mu Sv/h at 1 m and 0.30 mu Sv/h at 2 m distance from the pati ents respectively. The dose rates were decreasing following a monoexpo nential 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 mu Sv in the waiting r oom, 26 mu Sv for nurses working in the ward and 105 mu Sv for persons living in the same household. Conclusion: Even at very restrictive as sumptions the doses were far below the maximum permissible dose to non -radiation workers set by radiation protection regulations (1.5 mSv pe r year).