[Delayed radionecrosis of the cerebral hemispheres following betatron electron beam irradiation for scalp cancer. Pathological and clinical findings in one case (author's transl)].

Three years following an irradiation by the Betatron's electron beam of an epithelioma in left parieto occipital area of the scalp in a female patient aged 77, early suffering from high blood pressure, a fatal pseudo-tumoral brain necrosis occurs presenting as a rapidly increasing from of Wernicke's aphasia. The necropsy shows intense radionecrosis lesions of the brain and the bone, free of any parenchymatous malignant proliferation note-worthy for the striking density of microvascular changes as previously described in radiation therapy. The case observed some years ago, allows to definite again the limits doses of the extracranial irradiations now estimated at 1760 rets. That is the "Nominal Standard Dose" (NSD) measured by rets and taking into account the number of seances (N) and the duration of irradiation (T) which would be to take the place of "the total dose" (D) (rads). These dosimetric criteria themselves must be adjusted to the age and the vascular features of each patient.