VENTILATION AND PERFUSION LUNG IMAGING - WHICH NEBULIZER

Three commercially available Tc-99(m)-diethylenetriamine pentaacetate (Tc-99(m)-DTPA) aerosol delivery nebulizers for lung ventilation imagi ng were investigated. Two were air-jet systems,'Optimist' (Medicaid) a nd 'Microcirrus' (Amersham), and one was an ultrasonic device (Europlu s). Altogether, 112 consecutive patients were scanned, 37 using the Op timist, 40 using the Microcirrus and 35 the Europlus. The age mix, FEV (1), FVC and PEER measurements of the patients in each group were simi lar. Each contained a proportion of patients with poor respiratory fun ction, with PEFR rates ranging from 30 to 582 1 min(-1) for patients s tudied with all systems. Ease of use, image quality and cost were eval uated as well as radioactive and microbiological contamination. The Op timist system gave the best combination of image quality and cost, and was associated with the lowest level of radioactive contamination. It also proved the most popular. Airborne contamination for all nebulize rs was lower than previously reported and was largely dependent on pat ient compliance. With poorly compliant patients, the contamination lev els are sufficient to warrant an extraction device. There was no evide nce of bacterial contamination of the nebulizers or tubing on repeated use over 5 days.