1. Department of Oral and Maxillofacial Surgery, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam, The Netherlands
2. International Docrates Cancer Center, Helsinki, Finland; Saukonpaadenranta 2, FI-00180, Helsinki, Finland
3. Section of Oral Maxillofacial Radiology, Department of Clinical Dentistry, Faculty of Medicine and Dentistry, University of Bergen, Årstadveien 19, 5009 Bergen, Norway
4. Sektionen för bild- och funktionsfysik, C2-63Karolinska Universitetssjukhuset, Huddinge, SE-141 86 Stockholm, Sweden