Contamination levels and doses to staff arising from the use of Technegas.

The aim of this work was to assess the levels of airborne activity and contamination arising from Technegas ventilation scintigraphy and to estimate doses to staff. The maximum air concentration was below the 99Tcm-derived air concentration limit and considerably lower than reported levels for conventional radioaerosols. The level of contamination on staff gloves and aprons exceeded the body surface contamination limit in 63 and 9% of cases, respectively. Levels of contamination and air concentration were generally higher if the patient had difficulty with the administration procedure. Room surface contamination was very low. In 24% of cases activity was detectable on staff (either in the hair or nose) using gamma camera imaging. Annual skin doses from these sources are calculated to be below the limit for deterministic effects. Whole body effective doses are calculated to be similar to those received by staff performing other nuclear medicine studies. However, care should be exercised to keep exposure from both airborne and fixed sources to a minimum and a regular review of contamination levels is recommended. We recommend the wearing of gloves for all Technegas administrations and disposable hats and masks may be considered in certain cases.