Oertel, Michael; Elsayad, Khaled; Elsayad, Khaled Abdelsalam Mohamed Shahereldin; Kroeger, Kai; Haverkamp, Uwe; Haverkamp, U.; Rudack, Claudia; Lenz, Georg; Eich, Hans-Theodor; Eich, Hans Theodor; Eich, Hans Theodor; Eich, Hans Theodor: Impact of radiation dose on local control and survival in extramedullary head and neck plasmacytoma