Beijing;
Univ,;
Dept;
Radiol,;
Beijing;
100730,;
Peoples;
R;
China;
Beijing;
lnst;
Geriatr,;
Dept;
Cytol,;
Beijing;
100730,;
Peoples;
R;
China;
Beijing;
lnst;
Technol,;
Beijing;
100034,;
Peoples;
R;
China;
Tianjin;
Med;
Univ,;
Tianjin;
300070,;
Peoples;
R;
China;