Tertiary X-radiation-a problem for staff protection?

The influence of tertiary X-radiation on the radiological staff is widely unknown. Tertiary radiation is caused as the scattered radiation of the patient impacts the walls, floor, ceiling and surrounding air. The question that arises is does tertiary X-radiation provide a relevant contribution to the staff doses. The impact of tertiary radiation was investigated by means of measurements of the personal dose equivalent Hp(10) on an anthropomorphic Alderson Rando male phantom and also on operators/assistants staying in clinical practice. Further, the protective effect of lead foils, especially under tertiary radiation was also investigated. Correlations could be derived for clinical angiographic/interventional procedures between dose area products (DAPs) and dose length products (DLPs) vs. dorsal doses of staff persons. Generally, the staff doses that are a result of tertiary radiation depend on the X-ray energy and range from 0.15 to 0.55% of the scattered radiation impact caused by irradiation of the patient. Hence, a back panel with 0.125-mm lead equivalent is sufficient to protect the staff from tertiary radiation created within the room environment. (authors)