Interstitial photoacoustic spectral analysis: instrumentation and validation

Area of Science:

• Biomedical Optics
• Acoustic Imaging
• Medical Diagnostics

Background:

• Photoacoustic spectral analysis (PASA) quantifies molecular and microstructural tissue properties.
• Signal acquisition for PASA is limited in deep tissues due to optical and acoustic attenuation.
• Existing methods struggle to obtain high-quality signals from deeper biological locations.

Purpose of the Study:

• To develop an interstitial PASA approach for deep tissue analysis.
• To overcome signal limitations in deep tissue imaging for PASA.
• To create a novel fine needle PA probe for enhanced PASA.

Main Methods:

• Developed a fine needle photoacoustic (PA) probe integrating a fiber optics diffuser and a small aperture needle hydrophone.
• Implemented an interstitial PASA approach for signal acquisition in deep tissues.
• Tested the probe's efficacy in vitro and ex vivo.

Main Results:

• The needle probe successfully facilitated PASA in deep tissue locations.
• Quantified prostate cancer cell concentrations in vitro.
• Assessed lipid-infiltrated hepatocytes in liver tissue ex vivo.

Conclusions:

• The developed interstitial PASA needle probe is effective for deep tissue analysis.
• This approach shows potential for providing valuable pathologic information from tissues.
• The technology advances molecular and microstructural quantification in challenging biological samples.