[en] Since it is now possible to calculate the radiation fields used for medicinal purposes by means of radiation transport programs it was started to determine with mathematical models of radioeffects not only the physical effects or irradiation, but also the resulting biological radioresponses. This supplementary biologic information is not only of large general importance, but particularly valuable for the medicinal application of the biologically highly effective neutron radiation. With support by the Institute for Medicinal Radiophysics and Radiobiology of Essen University Hospital, and of two biomathematical working groups of Ulm University and Cologne University Hospital, who are experienced in the field of establishing mathematical models of the hematogenic cellular system, we developed out of experimental fundamental findings a cellkinetic, kybernetic model of the intestinal mucosa, which is highly sensitive to radiation. With this newly established model we succeeded for the first time in simulating comprehensively and quantitatively the time-dependent acute radioresponse of such a radiosensitive cellular system. For the first time we successfully used the computer simulation languages DARE-P and GASP, which are principally employed for solving problems in automatic control technology, and set up a radioresponse model. (orig.)