Quantitative analysis in medicine using photoacoustic tomography

Area of Science:

• Biomedical Optics
• Medical Imaging Physics

Background:

• Photoacoustic imaging (PAI) is a hybrid modality combining optical contrast with ultrasonic resolution.
• It relies on the photoacoustic effect: pulsed laser absorption leads to thermoelastic expansion and ultrasound wave generation.
• PAI demonstrates significant potential for non-invasive imaging of biological tissues, particularly vasculature.

Purpose of the Study:

• To review the challenges and potential solutions for quantitative photoacoustic imaging.
• To summarize methods for determining absolute and spatially resolved concentrations of endogenous and exogenous chromophores.

Main Methods:

• Review of existing literature on photoacoustic imaging principles and quantitative analysis.
• Discussion of factors affecting quantitative accuracy, including laser fluence, acoustic detection, and light propagation.
• Exploration of algorithms and models for absolute concentration retrieval.

Main Results:

• PAI offers high contrast and resolution, primarily visualizing blood distribution qualitatively or semi-quantitatively.
• Accurate quantification of chromophores (e.g., oxyhemoglobin, deoxyhemoglobin) remains a complex challenge.
• Limited studies have successfully addressed the demanding task of absolute quantification.

Conclusions:

• Quantitative photoacoustic imaging requires addressing significant technical hurdles related to light and sound interactions.
• Further research and development are crucial for realizing the full potential of PAI in precise biomedical diagnostics.
• Standardized methods for absolute quantification are needed to advance clinical translation.