1. Department of Physics, University of Patras, GR 265 04 Patras, Greece
2. Department of Medical Physics, University Hospital of Patras, GR 265 04 Patras, Greece
3. Department of Health Physics and Computational Intelligence, School of Health Rehabilitation Sciences, University of Patras, GR 251 00 Aigio, Greece
4. Department of Endovascular Neurosurgery/Interventional Neuroradiology, University Hospital of Patras, GR 265 04 Patras, Greece