[1] Canc Registry Norway, Sect Mammog Screening, POB 5313, N-0304 Oslo, Norway
[2] UiT Arctic Univ Norway, Dept Hlth & Care Sci, Tromso, Norway
[3] Univ Washington, Sch Med, Dept Radiol, Seattle, WA 98195 USA
[4] Univ Washington, Sch Publ Hlth, Dept Hlth Syst & Populat Hlth, Seattle, WA 98195 USA