Quantification in time-domain diffuse optical tomography using Mellin-Laplace transforms.

Area of Science:

• Biomedical Optics
• Medical Imaging
• Photon Transport

Background:

• Diffuse optical tomography (DOT) is a non-invasive imaging technique.
• Accurate quantification of optical properties in scattering media remains challenging.

Purpose of the Study:

• To evaluate time-domain DOT with Mellin-Laplace transforms for quantifying absorption perturbations.
• To assess the impact of inclusion depth and absorption change on quantification accuracy.

Main Methods:

• Numerical simulations and phantom experiments were conducted.
• Time-domain diffuse optical tomography utilizing Mellin-Laplace transforms was employed.
• Quantification of absorption coefficient changes (δμa) for centimetric objects at varying depths (1-2 cm) in turbid media.

Main Results:

• Estimated absorption coefficient showed near-linear behavior for changes up to 0.15 cm⁻¹.
• Underestimation factors of ~2, 3, and 6 were observed at depths of 1.0, 1.5, and 2.0 cm, respectively.
• Sublinear variation and ~20% decrease in accuracy were noted for larger absorption changes (δμa = 0.37 cm⁻¹).

Conclusions:

• Time-domain DOT with Mellin-Laplace transforms can quantify absorption perturbations.
• Inclusion depth significantly impacts quantification accuracy, leading to underestimation.
• Constraining absorption change to the inclusion volume can substantially enhance reconstruction accuracy and linearity.