Wide-field Frequency-domain Optical Tomography Imaging
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Solution Overview
Problem
Conventional near-infrared imaging systems, particularly those using continuous wave illumination, are limited in their ability to achieve high-density spatial sampling and fail to capture a rich set of optical properties of biological tissues, leading to inadequate image resolution and scanning speed.
Innovation Solution
The implementation of a wide-field frequency-domain imaging system that combines spatial and temporal encoding techniques using modulated light illumination and demodulation, enabling high-density spatial sampling and simultaneous amplitude/phase measurements for improved image reconstruction of tissue absorption and scattering properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional continuous wave illumination is used, then the system is simple to implement, but the spatial sampling density and image resolution are limited
Solution Approach 1:
The patent applies periodic action by using frequency-modulated illumination where the light source is modulated at a known frequency. This allows the system to encode spatial information temporally, enabling high spatial sampling density without requiring complex multi-element light sources. The periodic modulation creates measurable phase shifts that reveal tissue optical properties while maintaining system simplicity.
Solution Approach 2:
The system transitions from static continuous wave illumination to dynamic frequency-modulated illumination. By making the illumination time-dependent through frequency modulation, the system gains the ability to extract multiple optical properties simultaneously from a single measurement, thereby improving spatial sampling density without proportionally increasing system complexity.
2Loss of information
If conventional continuous wave illumination is used, then the system structure is simple, but the ability to capture rich optical properties is limited
Solution Approach 1:
Frequency modulation of the illumination source creates periodic variations in light intensity that encode multiple optical properties. By measuring the phase and amplitude changes of the modulated light through tissue, the system can simultaneously characterize absorption, scattering, and other optical properties that would otherwise require multiple separate measurements or complex system configurations.
Solution Approach 2:
The system changes the temporal parameters of the illumination by introducing frequency modulation. This parameter change enables the encoding of multiple optical properties within a single measurement cycle, allowing rich characterization of tissue optics without requiring proportional increases in system complexity or multiple independent measurement systems.
3Productivity
If fiber-coupled light delivery is used, then the system can achieve measurements, but scanning large tissue surfaces is time-consuming
Solution Approach 1:
The frequency-modulated illumination enables parallel measurement across the entire field of view by encoding spatial information temporally. Instead of sequentially scanning through different tissue regions using fiber-coupled delivery, the system can simultaneously illuminate and detect across the whole area, with the periodic modulation providing the temporal coding needed to resolve spatial information. This dramatically increases scanning speed and reduces measurement time.
Solution Approach 2:
The system transitions from spatial scanning (moving through space to measure different locations) to temporal encoding (measuring all locations simultaneously and resolving them through time-based modulation). By adding the temporal dimension through frequency modulation, the system achieves wide-field imaging without the time penalty of sequential scanning, effectively converting a 2D spatial problem into a 1D temporal solution.
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 results in significantly higher signal-to-noise ratios and scanning speed, allowing for detailed three-dimensional localization of tissue optical properties, overcoming the limitations of traditional fiber-based systems and enhancing the capability to resolve tissue heterogeneities.
Implementation Method 1
temporally-modulated light, via modulations with series of known waveforms
Implementation Method 2
a detector configured to detect light resulting from an interaction between the illumination beam and a sample
Implementation Method 3
subsequent demodulations of detected light signals with respect to these waveforms
Implementation Method 4
frequency-domain (FD) imaging and spectroscopy using intensity frequency-modulated illumination and phase-resolved detection have been shown to simultaneously recover absolute absorption and scattering tissue properties
Data Source
AI summary
Methods and systems for performing optical imaging are provided. An optical imaging system includes a light source configured to generate a spatially-distributed illumination beam of temporally-varying light and a detector configured to detect light resulting from an interaction between the illumination beam and a sample. The system further includes a processor configured to determine spatial and temporal characteristics of the detected light and generate a representation of the sample based on the determined spatial and temporal characteristics.