[1] Radiat Effects Res Fdn, Dept Clin Studies, Minami Ku, Hiroshima 7320815, Japan
[2] Kawasaki Med Sch, Dept Nucl Med, Kurashiki, Okayama, Japan
[3] Hamamatsu Univ Sch Med, Dept Orthoped, Hamamatsu, Shizuoka 43131, Japan
[4] Wakayama Univ, Sch Med, Dept Publ Hlth, Wakayama, Japan
[5] Osaka City Univ, Sch Med, Dept Internal Med, Osaka 545, Japan
[6] Radiat Effects Res Fdn, Dept Stat, Minami Ku, Hiroshima 7320815, Japan