Acute morphological changes induced in rat central nervous system by irradiation with high energy helium ions

Rats were irradiated with helium ions with an energy of 4 GeV/nucleon. Electron and light microscopes were used to investigate ultrathin slices from the vermis cerebelli and the cortex of the parietal area of the brain. Samples were taken 5 to 8 hours after irradiation. An extension of the area around the blood vessels in the white and grey matter of the brain was observed as was the formation of slots and the distancing between the bodies of the neurocytes, neurites, blood vessels and neuroglia cells in the cerebellum and the damage to the Purkynje cells and their immediate neighbourhood. In samples taken 70 to 72 hours after irradiation no differences were found as compared with non-irradiated controls. (M.D.)