Best-fit model parameters for the excess relative risk (ERR) of mammary tumors and dysplasias in mice treated with DMBA and/or irradiated with γ-rays and neutrons at high or low dose rates.

Parameter interpretations are: b = pre-malignant niche replication rate; δ = the parameter for homeostatic regulation of the number of pre-malignant cells per niche; XDMBA and Xg = cell initiation constants for DMBA and γ-rays; Krep = constant for repair of γ-ray-induced cell-initiating damage; Yn = neutron-induced bystander promotion constant; q = radiation dose rate at which 50% of all susceptible cells are activated by radiation-bystander signals under steady-state conditions; L = lag time between the appearance of the first malignant cell and tumor diagnosis.