M De Melis

Publications of M De Melis

• Argos 500: operation of a helmet vector-MEG.

  Authors: A Pasquarelli, R. Rossi, M De Melis, L Marzetti, A. Trebeschi, H P Müller, S N Erné

  Neurology & clinical neurophysiology : NCN. 02/2004; 2004:97.

  We here describe the MEG system recently installed at the University of Ulm; it is specifically designed for clinical application and routine use, to allow investigation of a large number of patientsWe here describe the MEG system recently installed at the University of Ulm; it is specifically designed for clinical application and routine use, to allow investigation of a large number of patients per day. To reach this goal, the system design meets the requirements of reliability, high field sensitivity, minimal set-up time before each measurement and an easy-to-handle user interface. The sensor system consists of a 163 vector-magnetometers array oriented and located in a suitable way to cover the whole head of the patient. Four additional triplets are available as references to arrange software gradiometers. The helmet shaped sensor system is positioned to accommodate the patient in a supine position. Simultaneously to the MEG, there are 64 EEG channels. Other relevant patient information can be recorded up to a total number of 660 acquisition channels. Noise level of a single magnetometer is about 5 fT/square root of Hz. Maximum sampling rate is 4200 Hz.

• Calibration of a vector-MEG helmet system.

  Authors: A Pasquarelli, M De Melis, L Marzetti, H P Müller, S N Erné

  Neurology & clinical neurophysiology : NCN. 02/2004; 2004:94.

  The MEG system Argos 500, recently installed at the University of Ulm, is designed for clinical application and routine use, to allow investigation of a large number of patients per day. To reachThe MEG system Argos 500, recently installed at the University of Ulm, is designed for clinical application and routine use, to allow investigation of a large number of patients per day. To reach this goal, the system design meets the requirements of reliability, high field sensitivity, minimal set-up overhead before each measurement and an easy-to-handle user interface.The sensor system consists of a 163 vector-magnetometer array oriented and located in a suitable way to cover the whole head of the patient. Four additional triplets are available as references to build software gradiometers. To use this system at a high performance level, it must be properly calibrated, with these goals: to determine the actual geometry of the sensors array, which can deviate from the design specifications, and to determine the actual sensitivity of each sensor. The calibrating source consists of 31 coils placed at the corners of a head-size dodecahedron. Various details of the calibration system and process are presented here.