[The dose-volume factor in radiotherapy. Significance of the focal or tumor volume for the evaluation of radiotherapeutic effect].

The absorbed energy dose, in dependence on the irradiated tissue volume or tumor volume (dose-volume-relations) has great significance for the valuation of radiation injuries and of the prognosis of the disease. The present paper includes an analysis, formal demonstrations and interpretation of these relations. Clinical observations and radiobiological experiments in literature were the basis of the present investigation. The assessment is kept simple, the models derived from it interprete well the clinical findings. Through these models, radiobiological findings and clinical experimental principles are connected. This results in a clear conception of the future development of irradiation planning, and the application technique of radiation. The range of validity of the cited models includes the treated volumes usual in radiotherapy. An extrapolation to the cellulary area or to the whole body may only be made with great reservations.