Multi-focus Photoacoustic Microscopy with Ultrasonic Array
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Solution Overview
Problem
Current high-resolution optical imaging techniques are insensitive to optical absorption, often require toxic exogenous dyes, and acoustic microscopic imaging provides limited functional information about biological tissue, especially for early-stage cancer.
Innovation Solution
The method employs multi-focus optical illumination with pulsed laser beams to induce photoacoustic emissions, detected by a high-frequency ultrasonic array, allowing for rapid reconstruction of images with optical resolution and reduced scanning requirements, using a combination of a microlens array or transmission grating for illumination and an ultrasonic array for detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical imaging techniques are used to achieve high spatial resolution, then imaging depth is limited to approximately one transport mean free path (about 1 mm), but the techniques are insensitive to optical absorption related to biochemical information
Solution Approach 1:
The patent combines optical excitation with acoustic detection to create photoacoustic microscopy. The system uses optical pulses to excite tissue and acoustic waves to detect the resulting photoacoustic signals, merging the advantages of both optical and acoustic imaging modalities to achieve both high spatial resolution and sensitivity to optical absorption.
Solution Approach 2:
The patent uses acoustic waves as an intermediary to transfer optical absorption information. When optical pulses excite the tissue, the absorbed energy generates acoustic waves that carry information about the optical absorption properties. The acoustic detection system then captures these waves, providing indirect access to optical absorption data with high spatial resolution.
2Measurement precision
If confocal microscopy or multi-photon microscopy is used to achieve high-resolution imaging, then imaging quality is improved, but toxic exogenous dyes must be introduced
Solution Approach 1:
The patent exploits the endogenous optical absorption properties of biological tissues, particularly hemoglobin in blood vessels, to generate photoacoustic signals. The system does not require exogenous contrast agents or dyes because the tissue's own optical absorption characteristics provide sufficient contrast for high-resolution imaging, eliminating toxicity concerns.
Solution Approach 2:
The patent utilizes the natural optical absorption spectra of biological chromophores, particularly the wavelength-dependent absorption of hemoglobin. By tuning the excitation wavelength, the system can selectively image different physiological components based on their intrinsic optical absorption properties, providing functional information without external agents.
3Reliability
If acoustic microscopic imaging is used to detect acoustic impedance variations, then flow information is obtained, but contrast for early-stage cancer is low and functional information is limited
Solution Approach 1:
The patent changes the detection parameter from acoustic impedance (used in conventional acoustic microscopy) to optical absorption. By measuring the optical absorption properties of tissue through photoacoustic signals, the system achieves high contrast for early-stage cancer detection and obtains functional information about tissue composition and physiology that is not accessible through acoustic impedance alone.
4Measurement precision
If single-focus optical illumination is used for photoacoustic imaging, then optical resolution is achieved, but scanning area is large and imaging speed is slow
Solution Approach 1:
The patent segments the optical illumination into multiple focused spots simultaneously using a microlens array or diffractive optical element. Each microlens focuses light to a separate spot in the tissue, allowing parallel excitation of multiple locations. The corresponding ultrasonic array detects signals from all spots simultaneously, achieving optical resolution while dramatically reducing scanning time and increasing imaging speed.
Solution Approach 2:
The patent transitions from one-dimensional sequential scanning to two-dimensional parallel illumination by arranging multiple optical foci in a spatial array. This dimensional expansion allows simultaneous imaging of multiple points across the field of view, converting a time-consuming sequential process into a parallel operation that maintains optical resolution while achieving high-speed imaging.
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 significantly reduces scanning area for 2D or 3D imaging, achieving high-speed optical-resolution photoacoustic imaging with finer spatial resolution and minimal background interference, suitable for clinical applications like intraoperative surgery and endoscopy.
Implementation Method 1
photoacoustic wave magnitude is, within certain bounds, linearly proportional to the optical absorption contrast
Implementation Method 2
The plurality of second light beams may cause the object of interest to emit acoustic signals
Implementation Method 3
receiving the acoustic signals from the object of interest using an ultrasonic transducer array
Implementation Method 4
splitting the first light beam into a plurality of second light beams using a beam-divider
Implementation Method 5
reflecting the first light beam toward the beam-divider using a movable scanning mirror
Implementation Method 6
focusing the plurality of second light beams on respective locations in an object of interest using a focusing device
Implementation Method 7
passing the plurality of second light beams through the optical-acoustic beam combiner to the focusing device and reflecting the acoustic signals entering the optical-acoustic beam combiner toward the ultrasonic transducer array
Data Source
AI summary
A probe for use with an imaging system, including a scanning device configured to receive a first light beam from a light source, a beam-divider configured to split the first light beam into a plurality of second light beams, and a focusing device configured to focus each of the second light beams on respective locations in an object of interest is disclosed.