[1] Rigshosp, Dept Oncol, Sect Radiotherapy, Copenhagen, Denmark
[2] Manchester Canc Res Ctr, Div Canc Sci, Manchester, Lancs, England
[3] Univ Copenhagen, Dept Clin Med, Fac Hlth & Med Sci, Copenhagen, Denmark
[4] Skane Univ Hosp, Dept Radiat Phys, Lund, Sweden
[5] Rigshosp, Dept Oncol, Copenhagen, Denmark
[6] Herlev Hosp, Dept Oncol, Copenhagen, Denmark