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 T c-99(m)-derived air concentration limit and considerably lower than re ported levels for conventional radioaerosols. The level of contaminati on 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 ver y low. In 24% of cases activity was detectable on staff (either in the hair or nose) using gamma camera imaging. Annual skin doses from thes e sources are calculated to be below the limit for deterministic effec ts. Whole body effective doses are calculated to be similar to those r eceived by staff performing other nuclear medicine studies. However, c are should be exercised to keep exposure from both airborne and fixed sources to a minimum and a regular review of contamination levels is r ecommended. We recommend the wearing of gloves for all Technegas admin istrations and disposable hats and masks may be considered in certain cases.