Navigated non-contact fluorescence tomography.

Area of Science:

• Biomedical Optics
• Medical Imaging
• Surgical Navigation

Background:

• Diffuse Optical Tomography (DOT) traditionally requires physical contact, limiting its use for real-time intraoperative imaging.
• Accurate localization of optical sources and detectors is crucial for reconstructing subsurface tissue properties.

Purpose of the Study:

• To develop and validate a non-contact DOT system integrated with surgical navigation for on-demand image updates.
• To improve the accuracy and precision of optical tomography in a surgical context.

Main Methods:

• A stereoscopic optical tracker was used for real-time localization of laser and camera components.
• Combined camera calibration and tracking data determined intrinsic camera parameters and spatial transforms.
• A multi-stage model converted camera data to surface flux, accounting for various optical and electronic factors.
• Finite-element DOT implementation projected source/detector positions onto a tissue mesh.

Main Results:

• Mean target registration errors for calibration were below 1 mm.
• Surface flux measurements in phantoms showed low mean errors (3.1% reflectance, 4.4% fluorescence) compared to diffusion theory.
• Inverse reconstructions accurately localized subsurface targets with an average centroid error of 0.44 mm.

Conclusions:

• The developed non-contact DOT system provides accurate, real-time imaging guidance.
• This technology shows promise for clinical applications in head and neck surgery, including tumor resection and lymph node mapping.