[Electron therapy]

The limited range of electrons yields depth doses and dose distributions offering the possibility to spare the tissue situated behind the tumor and to deliver a smaller volume dose. Electrons, therefore, can produce dose distributions being more favorable than those to be obtained with X-rays. The general radiation responses to electronic treatment are feeble. Clinical experiences also have shown that electrons are doing less harm to normal tissues than do X-rays. This may be derived from more important beta-effects and lesser alpha-effects of the electronic irradiation. The normal cells have a capacity for repair following beta-lesions which surpasses that of tumor cells, and thus, the electivity of electronic irradiation will increase and the clinical results are being explained. Schumacher (Berlin) has developed an improved fractionation schedule for electrons, using higher single doses once a week. The new schedule diminishes the number of tumor cells much more effectively than the conventional scheme utilized until now, and brings about, moreover, an additional protection of normal cells. Reoxygenation of anoxic tumor cells is sponsored. The clinical results from the new schedule (4262 cases) are very good.