Non-contact Oxygenation Assessment of Biological Tissues Based on a Time-of-Flight Method

Area of Science:

• Biomedical Optics
• Medical Instrumentation
• Photonics

Background:

• Accurate assessment of biological tissue oxygen saturation is vital for numerous medical applications.
• Non-contact measurement methods are highly desirable in clinical settings like emergency care and image-guided surgery to streamline procedures.
• Near-infrared spectroscopy is a key technology for tissue oxygenation, but non-contact measurements face challenges due to light scattering and precise distance estimation.

Purpose of the Study:

• To leverage time-of-flight (ToF) sensors for accurate, non-contact determination of biological tissue oxygenation (optical properties) and distance.
• To overcome the limitations of scattering in biological tissues for precise near-infrared measurements.

Main Methods:

• Development of model-based direct ToF (DToF) models tailored for highly scattering objects.
• Conducting simulation studies to ascertain optical properties and distances.
• Experimental validation using a tissue-mimicking phantom at varying distances (30 cm and 62 cm) with multi-spectral ToF measurements.

Main Results:

• Retrieved optical properties and distances showed high accuracy, with an average error of less than 0.5% compared to reference parameters.
• Multi-spectral ToF measurements successfully validated the simulation findings.
• The DToF approach demonstrated sensitivity to the optical properties of scattering objects.

Conclusions:

• A model-based direct ToF approach was successfully developed for precise, non-contact oxygenation measurements at a distance.
• This method shows significant potential for improving non-contact oxygenation assessment in diverse clinical scenarios.
• The findings pave the way for advanced non-contact diagnostic tools in healthcare.