Radiosensitive Structure of Metaphase and Interphase Hamster Cells as Studied by Low-Voltage Electron Beam Irradiation

Abstract

Electron beams of 3- to 50-keV energies were used to irradiate monolayers of hydrated metaphase and interphase hamster cells from in vitro cultures. Survival, defined as clone forming ability, was measured for a number of dose points and the ${\rm D}_{37}$ doses determined. Plots of ${\rm D}_{37}$ vs. beam voltage exhibited characteristic shapes which, when compared with analytically simulated dependencies, implied that the major radiosensitive structure is a thin peripheral shell close to the nuclear membrane in the interphase cells and a considerably thicker peripheral shell in metaphase cells. In addition the metaphase cells exhibited a fourfold greater sensitivity and a negligible shoulder on the survival curves.