Less radiation in a radiology department than at home

To compare the total work-related radiation dose in our department of radiology with the dose in Dutch residences, taking x-ray radiation, external natural radiation and radon into account.

Annual doses due to exposure to x-rays and external natural radiation were derived from the measured personal dose equivalent [H(p)(10)] of 144 workers. Additionally, departmental (222)Rn concentrations were assessed over 1 year.

The departmental radon concentration was 5 ± 1 Bq/m(3), the personal dose equivalent due to external natural radiation 0.32 ± 0.10 mSv/year, considerably lower than the average Dutch residential values of 13.5 Bq/m(3) and 0.88 mSv/year. As a consequence, working results in a lower dose than being at home as long as the x-ray-induced personal dose equivalent is lower than 1.25 mSv/year, which was the case for 131 of the 144 radiological workers, as well as for the whole group on average.

Working in our x-ray department results in a reduction in the collective effective dose, not an increase. The worldwide average radon concentration of 40 Bq/m(3), much higher than in the Netherlands, and the large decrease potentially achieved by the high ventilation rates common in hospitals, suggest that even considerably higher reductions are possible in other countries.