THE PHYSICAL AND CHEMICAL NATURE OF TECHNEGAS

Technegas, the discrete radio-aerosol particle, containing Tc-99m has been investigated, and the chemical evolution and physical properties of the particle demonstrated. Methods: A commercial technegas generato r was used to produce aerosols according to standard clinical procedur es, The aerosols were collected by electrostatic precipitation and exa mined with transition electron microscopy (TEM), scanning electron mic roscopy (SEM) and force microscopy, The chemical evolution was examine d by x-ray techniques and thermogravimetric analysis, Results: The act ive particle was identified as hexagonal platelets of metallic technet ium contained within a thin layer of graphitic carbon, This composite structure is discussed in light of the metal particle behaving as a te mplate for the carbon capsule, The average size of the observed hexago nal platelets, 30-60 nm, was only weakly dependent on the concentratio n of technetium in the crucible, Conclusion: The mechanism for the for mation of the technegas particles has been developed and the particles involved characterized. It appears that the use of other metals also leads to the formation of similiar materials.