1. Faculty of Medicine, University of Tartu, Tartu, Estonia
2. East-Tallinn Central Hospital, Tallinn, Estonia
3. Haematology and Oncology Clinic, Department of Radiotherapy and Oncological Therapy, Tartu University Hospital, Tartu, Estonia
4. Riga Stradiņš University, Riga, Latvia
5. Neurology Clinic, Department of Neurosurgery, Tartu University Hospital, Tartu, Estonia