Technegas, a carbon-coated Tc-99m nanoparticulate aerosol invented by Burch at the Australian National University in 1984, was introduced to the medical community in 1986 with two reports of its use as a new ventilation agent for lung imaging. Since that time, more than 1,500 Technegas machines have been distributed in hospitals and clinics in 54 countries, and more than 2 million Technegas ventilation studies have been completed. This review provides a synopsis of the more than 250 publications, abstracts and reports on Technegas. Technegas compares favourably with other commonly used ventilation (V) imaging agents including Xenon-133 and Krypton-81m gases, and several technetium-99m aerosol formulations. It is an effective agent for pulmonary ventilation (V) studies, particularly for detecting pulmonary embolisms when used in combination with perfusion (Q) scintigraphy by a technique known as ventilation/local perfusion image-mismatch (V/Q) imaging. Other applications for Technegas include non-clinical V/Q imaging in large animals, gastric emptying studies with Technegas-labeled meals, powder formulation studies of Technegas-labeled drugs, thrombosis detection using a precipitated formulation of Technegas (Thrombotrace) and pulmonary clearance studies using a derivative form called Pertechnegas.