Magnetocardiography measurements using an optically pumped magnetometer under ambient conditions

TL;DR

This paper presents a rubidium-based optically pumped magnetometer capable of measuring human cardiac magnetic fields in unshielded environments, with high sensitivity and potential clinical applications.

Contribution

Development of a portable, high-sensitivity magnetometer for unshielded magnetocardiography, demonstrating its effectiveness in real-world clinical settings.

Findings

Noise floor below 15 pT/√Hz in unshielded conditions

Reduced noise floor below 3 pT/√Hz with gradiometric configuration

Detected clear polarity reversal of QRS complex across thorax locations

Abstract

In this work, we report the development of a rubidium-based single-beam scalar optically pumped magnetometer (OPM) and demonstrate its application in measuring human cardiac magnetic fields in an unshielded environment. The developed magnetometers exhibit a noise floor below 15 pT/sqrt(Hz) in the frequency range of 1 to 35 Hz, with a measurement bandwidth of 100 Hz. When operated in a gradiometric configuration, the noise floor is further reduced to below 3 pT/sqrt(Hz) over the same frequency range. Magnetocardiography (MCG) signals were recorded at five different locations across the thorax. A clear polarity reversal of the QRS complex was observed across these measurement positions, confirming the spatial sensitivity of the system. The proposed system shows strong potential for clinical diagnostics, offering valuable physiological information through non-contact MCG measurements