The National Dose Registry cohort had previously been
linked internally to construct a unique dose history for each
member of the cohort (24, 26, 27). Incidence data were
obtained from the Canadian Cancer Data Base, derived from
the National Cancer Incidence Reporting System, and were
then linked internally to facilitate subsequent linkage to the
National Dose Registry file. This created a person-based
file, hereafter referred to as the incidence file. This file was
then linked to the National Dose Registry.