Fluorescence Diffuse Optical Tomography for Deep Tissue Localization
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Solution Overview
Problem
Current imaging techniques are limited in their ability to visualize deep tissue structures, particularly beyond 1 mm, due to light scattering and absorption, which hinders precise localization of fluorescent targets during surgical procedures.
Innovation Solution
A system and method utilizing diffuse optical imaging with fluorescence diffuse optical tomography (FDOT) that includes a light source, optical filter, and image capture device, coupled with computational processing to generate 3D geometric models and iteratively adjust parameters for accurate localization of fluorescent sources within tissue, enabling imaging beyond 1 mm depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If optical imaging methods are used to image deep tissue, then imaging depth can be extended beyond surface level, but light scattering and absorption severely limit the information that can be extracted and restrict imaging depth to less than 1 mm
Solution Approach 1:
The patent introduces a fluorescent agent as an intermediary substance that is selectively taken up by the tissue of interest. This agent converts the problematic scattered excitation light into directional fluorescent emission, which can be detected with much higher signal-to-noise ratio. The fluorescent agent acts as a mediator that transforms the imaging problem from direct transmission through scattering tissue to detection of emitted fluorescence, thereby extending effective imaging depth beyond 1 mm while preserving information quality
Solution Approach 2:
The patent changes the optical parameters by using fluorescent agents with specific excitation and emission wavelength characteristics. By selecting fluorescent agents whose emission wavelengths are in regions where tissue absorption is lower (such as the near-infrared window), and whose excitation wavelengths can penetrate tissue effectively, the system optimizes the balance between excitation light delivery and emission light detection, thereby extending imaging depth while maintaining information extraction capability
2Measurement precision
If feedback control of amplitude and phase of incident wavefront is used to focus light through tissue, then imaging resolution is improved, but imaging depth is still limited to less than about 1 mm
Solution Approach 1:
The fluorescent agent serves as an intermediary that eliminates the need for complex wavefront control to achieve deep tissue focusing. The agent is selectively taken up by target tissue and emits fluorescence when excited, providing intrinsic contrast that does not require precise optical focusing through scattering media. This approach maintains high measurement precision through selective uptake and emission while extending imaging depth beyond the 1 mm limitation of wavefront-controlled methods
3Difficulty of detecting and measuring
If fluorescent imaging is used to enable selective imaging of tissue of interest, then specific tissue can be identified, but light becomes highly scattered limiting the information that can be extracted
Solution Approach 1:
The fluorescent agent acts as an intermediary that resolves the contradiction between selective detection and information preservation. The agent is selectively taken up by target tissue (enabling specific identification) and converts scattered excitation light into directional fluorescent emission (preserving information). The selective uptake provides contrast for tissue identification while the emitted fluorescence carries quantitative information about tissue properties, overcoming the information loss problem caused by light scattering
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for precise localization of fluorescent targets, such as tumors, in deep tissue, facilitating guided surgery with improved depth information and reduced computational time, making it suitable for real-time surgical applications.
Implementation Method 1
a source of light configured to be shone on a subject, the light source configured to illuminate tissue of a subject at a first wavelength, and in response cause emission of light at a second wavelength from the tissue
Implementation Method 2
an optical filter configured to filter out light having the first wavelength and allow passage of light having the second wavelength
Data Source
AI summary
A method for identifying a source of florescence is disclosed which includes shining light on a subject at a first wavelength, causing emission of light at a second wavelength from the source of fluorescence, filtering out light at the first wavelength, capturing at least one 2 dimensional (2D) image of a subject having a plurality of pixels at the second wavelength, and establishing information about approximate location of a source of florescence within a tissue of the subject, selectively generating a 3D geometric model where the model is adapted to provide a model representation of the at least one 2D captured image, comparing the modeled at least one 2D captured image to the captured at least one 2D image and iteratively adjusting the model to minimize the difference, and outputting location and geometric configuration of the source of fluorescence within the tissue within the region of interest.