Human central nervous system lesions following radiation therapy

With the increasing number of high-energy irradiation sources, the cases of radiolesions of the CNS are also increasing. The irradiation effects on nerve and tumour tissue and the various kinds of irradiation damage are discussed. They become manifest as (a) acute radionecrosis (rare) and (b) late reactions which are subdivided into delayed lesions and the more frequently occurring late necrosis proper. In early and early-delayed lesions, morphologically local spongy demyelination with loss of the oligodendroglia and astrocytic reaction are seen while vascular damage is characteristic of late irradiation damage. The author's observations include clinic, pathology, and time/dose dependence of the irradiation damage of brain and spinal marrow. The tolerance values of the spinal cord and the relative biological effects of the irradiation are dealt with. In spite of a good knowledge of clinic and pathology of the radiolesions and the improvement of irradiation techniques, the widely differing individual reactions of the CNS to ionising rays remain partly unclear.