131I 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 131I among family members of patients treated with radioactive iodine. Thyroid activity measurements of 131I 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 131I 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 131I 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 131I 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, χ2 and Yule Phi coefficient. These analyses revealed relationships between 131I activities in the thyroids of the examined individuals and their housing conditions as well as consumption of meals prepared by the patients.

Search for tritium in air in a room equipped with 14 MeV neutron generator with tritiated targets.

Eight documented tritiated targets were stored, as well as some very old targets with unknown activity, in a room equipped with an ING-114 14 MeV fast neutron generator. When the neutron generator was running, the tritiated targets were irradiated with a deuterium beam. The aim of this work is to determine the tritium content in the room's atmosphere, as well as the radiation exposure of workers in the room. In this study, isotopic exchange was assumed. This means that tritium from the targets diffused into the air, where it reacted immediately with oxygen particles to form vapour. These vapour molecules diffused into open vessels containing deionized water (50 ml in 120 ml plastic containers). Fifty vessels were arranged along the length (every 0.50 m) and width (every 1 m) of the room. Additionally, there were three vessels placed in the room for shorter periods (5, 7, and 12 days) together with a vessel that was exposed to the tritium for the full duration of the experiment (18 days) to determine the saturation curve. Based on the measured tritium contents, a map of the spatial distribution of tritium in the room was created. The results were used to calculate the radiation dose for a person working in the room and showed no significant contribution to the approved average annual dose for workers.

131I INTERNAL CONTAMINATION AND COMMITTED DOSE ASSESSMENT AMONG NUCLEAR MEDICINE MEDICAL PERSONNEL.

This study presents 131I thyroid activity measurements of 56 employees of the Department of Nuclear Medicine and Endocrine Oncology, Centre for Oncology in Gliwice. The research instrument was a whole-body spectrometer. In 44 out of 56 examined staff members, the determined 131I activity was found to be above the detection limit. The measured activities ranged from 6 ± 2 to 457 ± 118 Bq. The maximum estimated committed effective dose reached was 1.5 mSv/y. The results were compared with previous measurements conducted in another Polish nuclear medical unit. From this comparison, we can see that radiological safety among nuclear medicine personnel can be improved by appropriate work organisation. Reducing exposure of workers can be achieved by properly organised turnovers concerning the most vulnerable worksites. In addition, to lower the radiation risk, it is essential to comply strictly with the isolation regime for the patients.

Measurement of 131I activity in thyroid of nuclear medical staff and internal dose assessment in a Polish nuclear medical hospital.

This paper presents results of 131I thyroid activity measurements in 30 members of the nuclear medicine personnel of the Department of Endocrinology and Nuclear Medicine Holy Cross Cancer Centre in Kielce, Poland. A whole-body spectrometer equipped with two semiconductor gamma radiation detectors served as the basic research instrument. In ten out of 30 examined staff members, the determined 131I activity was found to be above the detection limit (DL = 5 Bq of 131I in the thyroid). The measured activities ranged from (5 ± 2) Bq to (217 ± 56) Bq. The highest activities in thyroids were detected for technical and cleaning personnel, whereas the lowest values were recorded for medical doctors. Having measured the activities, an attempt has been made to estimate the corresponding annual effective doses, which were found to range from 0.02 to 0.8 mSv. The highest annual equivalent doses have been found for thyroid, ranging from 0.4 to 15.4 mSv, detected for a cleaner and a technician, respectively. The maximum estimated effective dose corresponds to 32% of the annual background dose in Poland, and to circa 4% of the annual limit for the effective dose due to occupational exposure of 20 mSv per year, which is in compliance with the value recommended by the International Commission on Radiological Protection.