[Vector magnetometer module for biomagnetic measurements].
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Animals↗
Biomedical subjects
D Drung
Publications and source records attributed to D Drung.
Magnetometry of evoked fields from human peripheral nerve, brachial plexus and primary somatosensory cortex using a liquid nitrogen cooled superconducting quantum interference device.
Superconducting Quantum Interference Devices (SQUIDs) can be used to detect neuromagnetic fields evoked in the peripheral and central nervous system. Up to now, such measurements had to be based on SQUIDs with a low critical temperature (Tc) requiring liquid helium cooling. Recent improvements in high-Tc SQUID technology relying on liquid nitrogen cooling led to a significant reduction in the system's noise level. Hare, first high-Tc recordings of weak neuromagnetic fields are demonstrated. In particular, along the entire somatosensory afferent pathway including peripheral nerves, brachial plexus and primary somatosensory neocortex evoked neuromagnetic activities were detected using conventional recording parameters for bandwidth and number of averages. This opens up a wide perspective for cost-effective high-Tc magnetometry in clinical neuroscience.
Brachial Plexus↗
A 37-channel DC SQUID magnetometer system.
A 37-channel DC SQUID magnetometer system has been built for biomagnetic studies. The SQUID loop of each magnetometer serves as the active sensing element, thereby eliminating the need for flux coupling circuits. The magnetometers are located approximately 3 cm above the outer dewar bottom. The SQUIDs are directly coupled to highly simplified read-out electronics using only five wires per channel; no helium temperature impedance matching circuits are required. Each channel can be independently inserted into or removed from the dewar. Using a novel electronic noise reduction technique the system white and 1 Hz flux density noise values are typically 5 and 10 fT Hz-1/2, respectively, including the noise contribution of the in-house fabricated dewar and the magnetically shielded room. The two parts of the data-processing system allow independent handling of the acquisition and analysing task. Two example measurements demonstrate the advantage of the electronic noise reduction method.
Equipment Design↗