Comparison of data on Mutation Frequencies of Mice Caused by Radiation - Low Dose Model -

TL;DR

This paper introduces the LD model, an extension of the LDM model, to estimate biological damage from low-dose radiation, successfully reproducing mutation frequency data in mice and analyzing dose-rate effects.

Contribution

The paper presents the LD model that incorporates cell death, repair, and proliferation effects to better estimate mutation frequencies from low-dose radiation exposure.

Findings

LD model reproduces mutation frequency data accurately.

The model explains dose-rate dependence using DREF.

Results align with extensive 'Mega-mouse project' data.

Abstract

We propose LD(Low Dose) model, the extension of LDM model which was proposed in the previous paper [Y. Manabe et al.: J. Phys. Soc. Jpn. 81 (2012) 104004] to estimate biological damage caused by irradiation. LD model takes account of all the considerable effects including cell death effect as well as proliferation, apoptosis, repair. As a typical example of estimation, we apply LD model to the experiment of mutation frequency on the responses induced by the exposure to low levels of ionizing radiation. The most famous and extensive experiments are those summarized by Russell and Kelly [Russell, W. L. & Kelly, E. M: Proc. Natl Acad. Sci. USA 79 (1982) 539-541], which are known as 'Mega-mouse project'. This provides us with important information of the frequencies of transmitted specific-locus mutations induced in mouse spermatogonia stem-cells. It is found that the numerical results of the mutation frequency of mice are in reasonable agreement with the experimental data: the LD model reproduces the total dose and dose rate dependence of data reasonably. In order to see such dose-rate dependence more explicitly, we introduce the dose-rate effectiveness factor (DREF). This represents a sort of preventable effects such as repair, apoptosis and death of broken cells, which are to be competitive with proliferation effect of broken cells induced by irradiation.