High-resolution electron microscopy of technegas and pertechnegas.

Once inhaled, technegas remains in the lungs for a long period of time, whereas pertechnegas rapidly disappears. To investigate this difference, the morphology of technegas and of pertechnegas was investigated using high-resolution transmission electron microscopy. The technegas and pertechnegas were generated in an atmosphere of pure argon and in 3% oxygen in argon, respectively, using a commercially available technegas generator. For the technegas, the technetium crystals were observed to be covered with carbon, whereas they were found to have no carbon coating with the pertechnegas. Whether or not the technetium is coated with carbon appears to be responsible for the differences in behaviour of technegas and pertechnegas after deposition on the lung epithelium following inhalation.