Radiotherapy and the mechanism of biological radiation effect

The characteristic shapes of survival curves were used in the discussion of some of the laws concerning the biological radiation effects on the cell. The hit theory is explained and the meaning of a large number of physical and chemical processes is studied. The influence of these processes was included into a general model of radiobiological mechanisms which was also mathematically described by a system of simple differential equations. The system was solved under certain, approximative conditions (at low dose rates). Using experimental data obtained from HeLa cells and using mathematical minimizing procedures, an appraisal was made of the influence of individual processes on the final effect. The importance of survival curves for improving the results of radiotherapy is discussed. (author)