[1] HOSP UNIV PENN, DEPT RADIOL, 1 SILVERSTEIN PAVILLION, 3400 SPRUCE ST, PHILADELPHIA, PA 19104 USA
[2] HOSP UNIV PENN, DEPT PATHOL, PHILADELPHIA, PA 19104 USA
[3] HOSP UNIV PENN, DEPT RADIAT THERAPY, PHILADELPHIA, PA 19104 USA
[4] UNIV UPPSALA, DEPT ORTHOPAED SURG, S-75105 UPPSALA, SWEDEN