Optical Interference Apparatus for Multi-Depth OCT Imaging
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Solution Overview
Problem
Current optical coherence tomography (OCT) probes face challenges in achieving focused images over depth, incorporating moving parts within the patient's body, and providing simultaneous endoscope viewing and interferometry, which limits their practicality and effectiveness in medical applications.
Innovation Solution
The solution involves an optical coherence tomography apparatus that records interferograms for multiple focal depths, uses a scanner at the proximal end of the probe to avoid moving parts within the patient, and integrates a viewing channel with interferometry using a beam-splitter to allow simultaneous visible light illumination and OCT imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a mechanical depth scanning system is used in time domain OCT to achieve focused images at different depths, then image focus quality is improved, but the acquisition speed deteriorates and mechanical complexity increases
Solution Approach 1:
The patent divides the single optical beam into multiple parallel beams, each focused at a different depth within the tissue. This segmentation allows simultaneous acquisition of depth-resolved information from multiple focal planes without mechanical scanning, thereby improving acquisition speed while maintaining focus quality through optical division of the measurement function.
Solution Approach 2:
The patent replaces the mechanical depth scanning system with an optical beam splitting and focusing system. Instead of physically moving the focus through mechanical means, multiple beams are optically directed to different depths simultaneously, eliminating mechanical moving parts and enabling faster acquisition while maintaining imaging precision.
2Adaptability or versatility
If a scanner is placed within the probe shaft to enable lateral scanning, then scanning capability is improved, but device complexity and difficulty of sterilization increase due to moving parts inside the patient's body
Solution Approach 1:
The patent extracts the scanning function from the internal probe shaft and relocates it to an external scanner positioned outside the patient's body. The probe shaft contains only stationary optical components for delivering and collecting light, while lateral scanning is performed externally by deflecting the incident beam, thereby eliminating moving parts within the sterile field and simplifying probe design.
Solution Approach 2:
The patent introduces an external scanner as an intermediary device that performs the scanning function remotely. The scanner acts as a mediator between the control system and the probe, allowing lateral scanning to be achieved without placing mechanical scanning components inside the probe shaft or within the patient's body, thus reducing device complexity and facilitating sterilization.
3Device complexity
If the same relay optical components are used for both viewing and interferometry, then device simplicity is improved, but optical path interference and image quality deteriorate
Solution Approach 1:
The patent applies different optical characteristics to different regions of the same optical component. The beam splitter is designed with wavelength-selective properties: it reflects infrared OCT beams while transmitting visible light for viewing. This local quality differentiation allows the same relay optical components to serve dual functions without interference, maintaining image quality for both modalities by optimizing each wavelength band's path through the shared optics.
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 enables sharper, deeper field-of-view images without moving parts inside the patient, allowing for more effective medical imaging while maintaining a normal endoscope viewing channel, improving both the depth and lateral resolution of OCT images.
Implementation Method 1
a beam-splitter positioned between the proximal end of the probe shaft, and the viewing apparatus and interference apparatus respectively, to separate the interferometer beams (in both directions) from the visible light beams (in both directions)
Implementation Method 2
OCT is based on the use of interferometry, where light in the measurement arm of an interferometer is passed to the object to be examined and a portion is scattered back to the interferometer. Light in the reference arm is passed to a mirror at a known distance and a reference beam is reflected back. The scattered measurement beam and the reflected reference beam are combined, and the interference between these two beams is detected
Implementation Method 3
an optical coherence tomography apparatus in which interferograms are recorded simultaneously for a plurality of different focal depths within the substance to be examined
Data Source
AI summary
An optical interference apparatus for carrying out Fourier domain optical coherence tomography. Multiple beams are provided and respective interferograms are recorded simultaneously for a plurality of different focal depths within a substance to be examined. Combined images are derived from the interferograms for a plurality of different focal depths, whereby a single image may be constructed with an increased depth of field. The axial spacing of the foci is calculated to take into account the Rayleigh range of the focal waist in the substance to be examined.