Optical Tissue Property Determination via Multi-Position Illumination
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Solution Overview
Problem
Current biomedical imaging techniques face challenges in accurately determining optical properties of specimens, such as reduced scattering and absorption, which are crucial for precise 3D representation of fluorescent light sources within scattering media, due to variations in tissue types and uncalibrated light sources leading to inaccurate light distribution models.
Innovation Solution
A method and apparatus for determining optical properties by sequentially illuminating a specimen at multiple positions with known light sources, measuring light emission, and using forward models to simulate light propagation, allowing for the correction of optical properties derived from Monte Carlo or Finite Element Model simulations to accurately represent internal light sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional 2D imaging data and photon diffusion models are used to produce 3D representation of fluorescent light sources, then 3D location, size and brightness can be determined, but the accuracy depends on the accuracy of optical property values input into the model which are often inaccurate due to tissue heterogeneity and uncalibrated light sources
Solution Approach 1:
The patent applies preliminary action by performing multiple calibration measurements at different illumination positions and wavelengths before conducting the actual imaging experiment. The system pre-determines optical properties (absorption coefficient μa and reduced scattering coefficient μs') by sequentially illuminating the specimen at multiple positions and measuring light emission, then uses these pre-determined values in the photon diffusion model to improve the accuracy of 3D light source representation without requiring complex real-time adjustments during imaging
Solution Approach 2:
The system applies self-service by using the specimen itself as both the object of study and the medium for calibration. The same specimen that will be imaged is used to determine its own optical properties through the calibration process, eliminating the need for separate reference samples or external calibration standards. The light source is calibrated using the specimen's tissue properties, and those calibrated properties are then used to accurately represent internal light sources in the imaging process
2Measurement precision
If light sources are not calibrated and tissue heterogeneity is not accounted for, then the imaging process is simpler and faster, but the accuracy of light distribution models and optical property determination deteriorates
Solution Approach 1:
The patent applies periodic action by sequentially illuminating the specimen at multiple discrete positions (e.g., 3-5 different locations) and at multiple wavelengths (e.g., 2-3 different wavelengths) in a systematic repeating pattern. This periodic measurement approach allows the system to gather comprehensive calibration data across the specimen's volume and spectral range, accurately determining spatially-resolved optical properties while maintaining a structured, efficient measurement sequence that minimizes total calibration time
3Measurement precision
If multiple illumination positions and wavelengths are used to determine optical properties, then accurate optical property values are obtained, but the measurement process becomes more complex and time-consuming
Solution Approach 1:
The patent applies parameter changes by systematically varying two key parameters during calibration: illumination position (spatial parameter) and wavelength (spectral parameter). The system measures light emission at multiple illumination positions (e.g., 3-5 positions across the specimen surface) and at multiple wavelengths (e.g., 2-3 excitation wavelengths), using these parameter variations to solve for both the absorption coefficient μa and reduced scattering coefficient μs'. This multi-parameter approach enables accurate determination of optical properties while the systematic variation strategy optimizes the balance between measurement comprehensiveness and acquisition time
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 provides more accurate optical property values for specimens, enabling precise 3D light source distribution analysis, reducing errors associated with heterogeneous tissue properties and improving the accuracy of internal light distribution models.
Implementation Method 1
providing light from a light source, having a first wavelength and a known illumination strength
Implementation Method 2
Photons emitted by labeled cells scatter in the tissue of the mammal, resulting in diffusive photon propagation through the tissue
Implementation Method 3
As the photons diffuse, many are absorbed
Implementation Method 4
The photons emitted from surface of the mammal can then be detected by a camera
Data Source
AI summary
Disclosed are apparatus and methods for determining accurate optical property values of turbid media. In one embodiment, the method includes (a) providing a light source, having a first wavelength and a known illumination power, sequentially at a plurality of specific illumination positions on a first surface of the specimen; (b) for each specific position of the light source, obtaining light emission measurements from a second surface of the specimen that is opposite the first surface, wherein the light emission measurements are obtained for a plurality of surface positions of the second surface; and (c) for each specific illumination position of the light source at the first surface of the specimen, determining one or more optical properties for the specimen based on the specific illumination position of the light source, the first wavelength of the light source, the known illumination power of the light source, and the obtained light emission measurements for such each specific illumination position. The optical properties for the plurality of specific illumination positions of the light source are individually determined for each specific illumination position of the light source.