A stochastic model of the effects of ionizing radiation on mammalian cells in vitro (Q792238)

A new, more realistic model of the action of ionizing radiation on mammalian cells growing in vitro is presented. Although this model requires a large number of parameters, these are linked to biologically observable quantities rather than being abstract sensitivities, as had previously been the case. Three different stochastic processes are required: \(\{\) X(t);\(t\in [0,\tau]\}\), representing damage alterations during irradiation; \(\{\) (X(t), \(S(t));t\in [\tau,\tau +T_ D]\}\), representing changes in both damage X(t) and cell cycle position S(t) during the post-irradiation cell cycle; and \(\{N_ x(t);t\in [0,T_ G]\}\), representing the subsequent colony growth process conditioned on the value of \(X(\tau +T_ D).\) The assumptions used to define these processes extend a previous model of short term DNA damage formation and repair [(\textit{S. J. Nelson}, Radiat. Res. 92, 120-145 (1982)] to include the influence of cell cycle progression on damage in the irradiated cell and the effect of permanent inherited damage on the daughter cells' colony growth pattern. Expressions corresponding to commonly measured radiation effects are derived from the model and compared with predictions from previous models.