Time-factor. Introduction of the Moderator

Abstract

The complex phenomena, which are summarized by the still rather ill-defined term “time-factor”, are concerned with time and dose rate influences on measurable biological effects produced by a determined radiation dose. Certainly, irradiation effects must show some form of time dependence, because irradiarion on rhe one hand is a rime-consuming procedure, and all possibiliries of consideration of living rhings on rhe orher, between birth and death and even before and afterwards, must be related to time. The results of such considerations are sometimes summarized by terms such as “evolution” or “development”, specifically historical terms. What we can really do in the observation of a biological system is to look at its topography or at its history. History, however, never returns exactly to former stages, though some phenomena may appear to an unskilled observer, to be periodic. Development, also every development after irradiation, is therefore the time sequence of irreversible changes.