ABSTRACT
The linear–quadratic dose–effect relationship for deoxyribonucleic acid (DNA) double strand breaks is extended to give equations for cell survival, chromosome aberrations and mutations per surviving cell by relating the double strand break lesion to each of the three cellular effects. The model proposes that, on the basis of the unineme structure of nuclear chromosomes where a single DNA double helix forms the backbone of a chromosome, a DNA double strand break is, in fact, a chromosome arm break. The DNA double strand break is a critical lesion which disrupts the mechanical and genetic integrity of a cell and, as the perfect repair of the double strand break cannot be guaranteed, it is a potentially mutagenic lesion. The micro-dosimetry problem arises from a radiation physics consideration of the derivation of the linear–quadratic dose–effect function for the induction of DNA double strand breaks and, more specifically, the derivation of the quadratic coefficient in the beta mode.
