1. ERGO SA, Athens, Greece
2. Department of Nephrology, Aretaeion Hospital, Athens, Greece
3. Centre for Measurement and Information in Medicine, City University, London, UK
4. IDATE, Montpellier Cedex, France
5. Department of Electronic Engineering, National Technical University of Athens, Greece
6. Department of Electronic Engineering, University of Patras, Greece
7. Regional Medical Physics Department, Newcastle upon Tyne, UK