Quantitative Photoacoustic Image Reconstruction using Fluence Dependent Chromophores

Area of Science:

• Biomedical optics
• Photoacoustic imaging
• Quantitative imaging

Background:

• Biomedical photoacoustic imaging (PAI) produces images based on absorbed optical energy density, not direct optical absorption.
• This relationship complicates quantitative analysis of chromophore concentration from PAI data alone.
• Accurate quantification is crucial for molecular and functional imaging applications.

Purpose of the Study:

• To develop a method for quantitatively estimating chromophore concentration in photoacoustic imaging.
• To overcome limitations of current PAI techniques that hinder accurate concentration measurements.
• To provide an alternative to model-based multiwavelength approaches for quantitative PAI.

Main Methods:

• Utilizing photoacoustic images acquired at progressively increasing illumination strengths.
• Exploiting the property of a specific chromophore whose absorption drops to zero above a threshold light fluence.
• Analyzing the spatial variation of chromophore concentration based on the acquired image series.

Main Results:

• Demonstrated the feasibility of estimating spatially varying chromophore concentration.
• The proposed technique successfully quantifies chromophore concentration under specific absorption conditions.
• The method relies on analyzing PAI data from varying illumination levels.

Conclusions:

• A novel approach enables quantitative photoacoustic imaging by estimating chromophore concentration.
• This technique offers an alternative to existing multiwavelength methods for accurate PAI.
• The findings open new avenues for photoacoustic molecular and functional imaging.