1. Section
of Biomedical Radiation Sciences, Department of Radiology, Oncology
and Radiation Science, Rudbeck Laboratory, Uppsala University, SE-751
85 Uppsala, Sweden
2. Ridgeview Instruments AB, Vänge, Sweden
3. Section
of Otolaryngology and Head and Neck Surgery, Department of Surgical
Sciences, Uppsala University, SE-751 85 Uppsala, Sweden