Fundamental effects of array density and modulation frequency on image quality of diffuse optical tomography

Area of Science:

• Biomedical optics
• Medical imaging technology

Background:

• Diffuse optical tomography (DOT) enables 3D imaging of chromophore changes in turbid tissues.
• Key optimization strategies include high-density (HD) source-detector arrays (<15 mm spacing) and high-frequency (∼100 MHz) modulated light.

Purpose of the Study:

• To elucidate the interaction between array density and modulation frequency for optimal DOT system design.
• To systematically evaluate the impact of these parameters on DOT image quality.

Main Methods:

• Simulated 32 DOT system designs with realistic noise.
• Quantified image quality metrics including localization error, spatial resolution, signal-to-noise ratio, and depth of field.
• Analyzed approximately 85,000 point spread functions per model.

Main Results:

• Array density demonstrated a stronger influence on image quality than modulation frequency.
• Image quality improvements plateaued for array densities with spacing closer than 9 mm.
• 300 MHz modulation frequency yielded the deepest reliable imaging for a given array density.

Conclusions:

• Both array density and modulation frequency influence spatial sampling, limited by photon diffusivity.
• Findings offer guidance for optimizing DOT systems for applications like wearable brain imaging and breast tumor detection.