Low dose, low dose rate and DREF values
Biophysical modelling is used to derive an analysis of the influence of dose rate on the shape of dose-effect relationships. Experimental results are used to support the basic tenets of the model that DNA double strand breaks are crucial lesions which can lead to cell killing, chromosomal aberrations and mutations. The model is extended to describe cell transformation and malignancy and, by combining this extension with the dose rate effect, an equation is derived to describe the Dose Rate Effectiveness Factor (DREF) as a function of dose. It is shown that for cell transformation per irradiated cell and for malignancy, the DREF increases with dose to a maximum value and then decreases at higher doses and can become less than one. A consideration of radiobiological data indicates that the maximum DREF value will rarely exceed 6.5 and that a range from 1.5 to 5 is more probable for sparsely ionising radiation. Although DREF is a varying function of dose, an example is given where a constant DREF could be used in radiological protection.
Bibliographic Reference: Paper presented: ESRB 23rd Annual Meeting, Dublin (IE), Sept. 23-26, 1990
Availability: Available from (1) as Paper EN 35598 ORA
Record Number: 199011620 / Last updated on: 1994-12-02
Original language: en
Available languages: en