Transmission Electron Microscopic Observations on Technegas and Pertechnegas

We examined the features of technegas, pertechnegas, and related nonradioactive aerosols using transmission electron microscopy. Samples of technegas, pertechnegas and unlabeled saline aerosols were created and collected within the Technegas Generator. The samples were examined by transmission electron microscopy and electron energy-loss spectroscopy (EELS). Technegas, pertechnegas, and the unlabeled saline aerosol particles have the same ultrastructure. Heating by the electron beam produces damage in some of these particles, revealing an opaque core material that is water soluble, and a thin surface layer. Disappearance of chlorine is noted by EELS during heating. We conclude that all of the examined aerosols have the same ultrastructure, regardless of the presence of small concentrations of oxygen during particle formation, and regardless of the presence of the technetium-99m label. We also note that some particles are susceptible to damage by heating; these consist of a thin surface layer and an opaque core substance that is dissipated upon heating.