Development of biological tissue-equivalent phantoms for optical imaging

Area of Science:

• Biomedical Optics
• Biophotonics
• Materials Science

Background:

• Optical properties of biological tissues are crucial for understanding light-tissue interactions.
• Variations in tissue color and composition significantly influence optical characteristics.
• Accurate optical characterization is essential for developing effective biomedical devices and therapies.

Purpose of the Study:

• To measure the surface backscattered profiles of fresh excised sheep tissues (heart, lungs, bone, muscle).
• To create optical phantoms with matching optical properties (absorption and scattering coefficients) to biological tissues.
• To validate the optical parameters of these phantoms using Monte Carlo simulations.

Main Methods:

• Utilized a multi-probe reflectometer to measure surface backscattered profiles of biological tissues.
• Prepared optical phantoms using paraffin wax and specific color materials to match tissue backscattered profiles.
• Employed Monte Carlo simulations to determine optical parameters (absorption coefficient (μa), reduced scattering coefficient (μs'), anisotropy factor (g)) of phantoms.

Main Results:

• Successfully created optical phantoms that replicate the surface backscattered profiles of biological tissues.
• Determined distinct optical parameters for different tissue types: lungs exhibited the highest absorption coefficient (1.0 cm⁻¹), while muscle had the lowest (0.02 cm⁻¹).
• Muscle showed the highest reduced scattering coefficient (21.2 cm⁻¹), and bone had the lowest (13.08 cm⁻¹).

Conclusions:

• Developed a method for creating reliable optical phantoms that mimic the optical properties of biological tissues.
• These phantoms serve as valuable tools for calibrating instruments and validating optical models in biophotonics research.
• The characterized optical parameters provide essential data for further investigations into light propagation in biological tissues.