Safe practice ventilation technique in lung scanning for pulmonary embolism

Ventilation/Perfusion scanning for suspected pulmonary embolism is undergoing a renaissance due to the advent of single-photon emission computed tomography (SPECT). The scan protocol demands the inhalation of a radioactive gas or vapour for the ventilation scan. The purpose of this article is to report the radioactive environmental contamination that can occur when Tc-99m Technegas vapours are administered to patients for the ventilation SPECT scan. This contamination can concentrate within gamma camera heads to degrade images and is also a radiation hazard to staff. A method for sequestrating this airborne contamination was investigated using an ultra-low particulate air filter. The prevalence of radioactive contamination and the levels of contamination captured were quantified and only 36% of patients were found to have undergone the ventilation procedure without producing significant airborne contamination. Advice is given on best practice that will minimize airborne contamination and minimize the risks to staff working in the Nuclear Medicine department. The use of an extraction/filtration device may be seen as an effective additional control measure against airborne radioactive contamination for health professionals.