Dose-response relationship

In general, this is the functional relationship between the size of dose of a substance and the extent of the response to it. For example, with a linear dose-response relationship the dose and response are always in the same proportion, that is half the dose yields half the response, one tenth of dose yields one tenth of response et cetera. A linear dose-response relationship would mean, for example, that one per cent of radiation dose will cause one per cent of cases. However, it is quite possible that there is a threshold of dose below which body cells are able to repair radiation injuries except for extremely few mistakes. There would be practically no case that could occur below this dose threshold (threshold value).