1. Group Health Research Institute, Seattle, Washington
2. Department of Radiology, University of Washington, Seattle Cancer Care Alliance, Seattle
3. Department of Community and Family Medicine, Norris Cotton Cancer Center, Dartmouth Medical School, Hanover, New Hampshire
4. General Internal Medicine Section, Department of Veterans Affairs, San Francisco, California5Department of Medicine, University of California, San Francisco6Department of Epidemiology and Biostatistics, University of California, San Francisco
5. Department of Radiology, University of North Carolina, Chapel Hill
6. Department of Family Medicine, University of Vermont, Burlington9Department of Radiology, University of Vermont, Burlington
7. Department of Medicine, University of California, San Francisco