Towards acousto-optic tissue imaging with nanosecond laser pulses

Area of Science:

• Biomedical Optics
• Acousto-Optics
• Laser-Tissue Interaction

Background:

• Acousto-optic (AO) methods are valuable for probing biological tissues.
• Speckle decorrelation poses a significant challenge for in-vivo AO measurements.
• Existing AO techniques struggle with dynamic tissue changes and ultrasound propagation.

Purpose of the Study:

• To present a novel method for generating acousto-optic signals in tissue-like media.
• To overcome the speckle decorrelation problem in acousto-optic measurements.
• To enable combined acousto-optic and photoacoustic measurements in a single setup.

Main Methods:

• Utilized nanosecond laser pulses interacting with tissue-like media.
• Recorded and analyzed speckle patterns with and without simultaneous ultrasound application.
• Employed stroboscopic ultrasound application to visualize temporal speckle behavior.
• Investigated speckle pattern addition and subtraction at various ultrasound phases for quantification.
• Compared the novel methods with the established 2D speckle contrast method.

Main Results:

• Successfully generated acousto-optic signals in tissue-like media.
• The proposed methods for quantifying the acousto-optic effect performed similarly to the speckle contrast method.
• Demonstrated a potential solution to the speckle decorrelation issue in acousto-optics.

Conclusions:

• The developed method advances in-vivo acousto-optic measurements by mitigating speckle decorrelation.
• This technique paves the way for more robust and reliable optical probing of biological tissues.
• The setup facilitates the integration of acousto-optics and photoacoustics, enhancing diagnostic capabilities.