12チャンネル高分解能SQUID磁束計を用いたラットの心磁図計測  [in Japanese] Measurement of Magnetocardiograms of Rats Using a 12-Channel High-Resolution Dc-SQUID Magnetometer  [in Japanese]

We developed a multi-channel high-resolution SQUID magnetometer for measuring biomagnetic fields produced by small animals. Using this system, we measured magnetocardiograms (MCGs) of rats. The specifications of our system are as follows: pick-up coils 5mm in diameter located on a 7.5-mm grid, a 15-mm gradiometer base-line, a one-turn pick-up coil, and a distance of 5mm between the pick-up coil and the outside surface of the dewar. The field sensitivity was 100-ft/√Hz in the white-noise frequency. Five adult rats, ranging in weight from 0.2 to 0.4kg, were used in the study. The rats were anesthetized intraperitoneally with nembutal (40mg/1kg). The number of magnetocardiogram signals averaged 2000, with the QRS wave as the trigger. The topographies of P-waves, QRS-waves and T-waves of MCG were analyzed. We concluded that the system used in this study is useful for physiological studies of small animals.