Low Temperature-Mediated Enhancement of Photoacoustic Imaging Depth

TL;DR

Lowering the temperature of the medium in photoacoustic imaging enhances imaging depth by reducing background noise, primarily through changes in the Grüneisen parameter, offering new biomedical refrigeration applications.

Contribution

This study provides both theoretical and experimental evidence that cooling the intermediate medium improves photoacoustic imaging depth by altering optical and acoustic properties.

Findings

Imaging depth increases with lower temperature.

Cooling reduces background noise via Grüneisen parameter decrease.

Enhanced SNR leads to better imaging performance.

Abstract

We study the temperature dependence of the underlying mechanisms related to the signal strength and imaging depth in photoacoustic imaging. The presented theoretical and experimental results indicate that imaging depth can be improved by lowering the temperature of the intermediate medium that the laser passes through to reach the imaging target. We discuss the temperature dependency of optical and acoustic properties of the intermediate medium and their changes due to cooling. We demonstrate that the SNR improvement of the photoacoustic signal is mainly due to the reduction of Gr\"uneisen parameter of the intermediate medium which leads to a lower level of background noise. These findings may open new possibilities toward the application of biomedical laser refrigeration.