1. Department of Women's and Children's Health; Childhood Cancer Research Unit, Karolinska University Hospital and Karolinska Institute; Stockholm Sweden
2. Department of Radiology; Helsinki University Central Hospital; Helsinki Finland
3. Department of Pediatrics and Adolescent Medicine; The University Hospital Rigshospitalet; Copenhagen Denmark
4. Division of Pediatric Hematology-Oncology and Stem Cell Transplantation; Children's Hospital; University of Helsinki and Helsinki University Hospital; Finland
5. Department of Pediatrics; Division of Pediatric Hematology-Oncology and Stem Cell Transplantation; Sahlgrenska University Hospital; Gothenburg Sweden
6. Department of Pediatrics; Aarhus University Hospital; Aarhus Denmark