Angle correction for small animal tumor imaging with spatial frequency domain imaging (SFDI)

Area of Science:

• Biomedical optics
• Medical imaging
• Optical engineering

Background:

• Spatial frequency domain imaging (SFDI) enables quantitative tissue optical property extraction.
• SFDI is promising for small animal tumor imaging but suffers artifacts on curved surfaces like tumor edges.

Purpose of the Study:

• To develop and validate an angle correction method for SFDI to mitigate artifacts on curved surfaces.
• To improve the accuracy of optical property and chromophore extraction in small animal tumor models.

Main Methods:

• A modified Lambertian angle correction, adapted from satellite imagery's Minnaert correction, was developed.
• The method accounts for tissue surface angles up to 75 degrees.
• Validation was performed using a hemisphere phantom and a small animal tumor model.

Main Results:

• The proposed angle correction significantly reduced absorption coefficient (µa) extraction errors by 64% and scattering coefficient (µs`) extraction errors by 16%.
• The method yielded more physiologically relevant optical property and chromophore values for tumors.
• Artifacts on highly curved surfaces were substantially mitigated.

Conclusions:

• The modified Lambertian angle correction effectively addresses SFDI artifacts on curved surfaces.
• This technique enhances the reliability of quantitative optical property measurements in small animal tumor imaging.
• The improved accuracy supports the clinical translation of SFDI for preclinical research.