CELL-SURVIVAL AFTER AUGER-ELECTRON EMISSION FROM STABLE INTRACELLULARINDIUM EXPOSED TO MONOCHROMATIC SYNCHROTRON-RADIATION

The biological effect of Auger electrons emitted from indium in V79 ce lls was investigated. K-shell vacancies were induced by synchrotron x- rays, Two energies, 100 eV above and below the K-edge of indium, were used. The cell survival for controls was similar to that which has bee n reported by others, with D-37 = 4.4 Gy. Indium-oxine-labelled cells exhibited a survival clearly below that of the controls, D-37 = 3.2 Gy , but no significant difference in survival between irradiations above and below the K-edge could be observed, The explanation is, inter ali a, that the number of photons interacting with indium atoms incorporat ed into the cell, is small compared with the number of photons interac ting with other atoms in the cell, The toxicity of indium oxine made i t impossible to incorporate a sufficient number of indium atoms into t he cells to observe a difference in this study, However, monoenergetic irradiation above and below the K-edge, provides a technique for the investigation of basic biological effects of Auger processes.