131 I thyroid activity and committed dose assessment among family members of patients treated with radioactive iodine

The main goal of the present study was estimation of an internal contamination of 131 I among family members of patients treated with radioactive iodine. Thyroid activity measurements of 131 I in examined volunteers were performed using a whole-body spectrometer at the institute of nuclear physics, Polish academy of sciences. During this research, 20 relatives of patients treated with 131 I were examined: eight women and 12 men with an age in the range from 3 to 72 years. In the case of nine individuals, the activity of 131 I in the thyroid was below the detection limit, but among the remaining 11 individuals, the activity varied from (9 ± 3) Bq up to (1140 ± 295) Bq. Subsequently, based on the measurements of thyroid 131 I activities, the corresponding doses were assessed. The highest estimated effective dose reached 218 μSv, while the thyroid equivalent dose was 2.4 mSv. In addition, the experimental data obtained were statistically analysed together with the results of surveys of the individuals participating in the study by means of correspondence analysis and nonparametric tests: Mann–Whitney, gamma, χ 2 and Yule Phi coefficient. These analyses revealed relationships between 131 I activities in the thyroids of the examined individuals and their housing conditions as well as consumption of meals prepared by the patients.