[1] Oregon Hlth & Sci Univ, Qual Dept, St Charles Hlth Syst, Portland, OR 97201 USA
[2] Oregon Hlth & Sci Univ, Dept Radiat Med, Portland, OR 97201 USA
[3] Univ Texas Med Sch Houston, Houston, TX USA
[4] Geisel Sch Med Dartmouth, Dartmouth Inst Hlth Policy & Clin Practice, Hanover, NH USA