CN-122004746-A - Handheld multispectral photoacoustic imaging device and method for dry eye detection

CN122004746ACN 122004746 ACN122004746 ACN 122004746ACN-122004746-A

Abstract

The invention discloses a handheld multispectral photoacoustic imaging device and method for dry eye detection, wherein the device comprises a multispectral photoacoustic signal excitation module, an MEMS scanning imaging module and a data acquisition and control module, the multispectral photoacoustic signal excitation module is used for generating three laser beams with different wavelengths, the three laser beams are coupled into a transmission optical fiber, the MEMS scanning imaging module is used for reflecting the laser beams of the transmission optical fiber to realize optical scanning and excitation of a sample to be detected and converting a photoacoustic signal into an electric signal, the data acquisition and control module is used for preprocessing the electric signal and performing analog-to-digital conversion on the preprocessed electric signal to form a digital signal, and the multispectral photoacoustic signal excitation module and the MEMS scanning imaging module are synchronously controlled. The invention constructs a multi-mode imaging-multi-parameter evaluation system integrating structure, function and mechanical information, and provides support for early diagnosis, parting evaluation and pathological mechanism research of xerophthalmia.

Inventors

CHEN ZHONGJIANG
Zhong Houli
TANG QUN
CHEN YUMING
ZHANG SHUYUE

Assignees

福建医科大学

Dates

Publication Date: 20260512
Application Date: 20260210

Claims (10)

1. The handheld multispectral photoacoustic imaging device for dry eye detection is characterized by comprising a multispectral photoacoustic signal excitation module, an MEMS scanning imaging module and a data acquisition and control module; The multispectral photoacoustic signal excitation module comprises a first laser signal excitation unit and a second laser signal excitation unit, wherein the first laser signal excitation unit is used for generating first specific wavelength laser, the second laser signal excitation unit is used for generating second specific wavelength laser and third specific wavelength laser, and the first specific wavelength laser, the second specific wavelength laser and the third specific wavelength laser are coupled into a transmission optical fiber; The MEMS scanning imaging module is used for reflecting the laser of the transmission optical fiber, realizing optical scanning and excitation of the sample to be tested and converting the photoacoustic signal into an electric signal; The data acquisition and control module is used for preprocessing the electric signals, carrying out analog-to-digital conversion on the preprocessed electric signals to form digital signals, and synchronously controlling the multispectral photoacoustic signal excitation module and the MEMS scanning imaging module.
2. The handheld multispectral photoacoustic imaging apparatus of claim 1, wherein the first laser signal excitation unit comprises a first pulsed laser, a first linear polarizer, a first half-wave plate, a first fiber coupler, a first polarization maintaining fiber, a first collimating mirror, a first bandpass filter, a first mirror, and a first dichroic mirror; The laser output by the first pulse laser sequentially passes through the first linear polaroid and the first half wave plate to carry out polarization regulation and control, is injected into the first polarization maintaining optical fiber by the first optical fiber coupler, generates a laser spectrum through nonlinear optical effect in the first polarization maintaining optical fiber, and after being collimated by the first collimating mirror, selects a first specific wavelength through the first bandpass filter and is guided to the first dichroic mirror by the first reflecting mirror.
3. The handheld multispectral photoacoustic imaging apparatus of claim 1, wherein the second laser signal excitation unit comprises a second pulsed laser, a beam splitter, a second dichroic mirror, a second linear polarizer, a second half-wave plate, a second fiber coupler, a second polarization maintaining fiber, a second collimating mirror, a second bandpass filter, a third mirror, and a third dichroic mirror; The laser output by the second pulse laser is divided into two paths by a beam splitter, wherein one path takes the central wavelength of the second pulse laser as a second specific wavelength and is directly output to a second dichroic mirror as fundamental frequency light, the other path sequentially passes through a second linear polarizer and a second half-wave plate to carry out polarization regulation and control after being reflected by the second reflecting mirror, a second polarization maintaining optical fiber is injected by a second optical fiber coupler, a broadband laser spectrum is generated by the nonlinear optical effect in the second polarization maintaining optical fiber, a third specific wavelength is selected by a second bandpass filter after the collimation of a second collimating mirror, and the third specific wavelength is guided to a third dichroic mirror by a third reflecting mirror.
4. The handheld multispectral photoacoustic imaging apparatus of claim 1, wherein the MEMS scanning imaging module comprises a third collimating mirror, an objective lens, a MEMS micro-vibrating mirror, and an ultrasound transducer; the laser of the transmission optical fiber is collimated into parallel beams by the third collimating mirror, the parallel beams are converged by the objective lens and reflected by the MEMS micro-vibrating mirror to realize two-dimensional scanning deflection, the beams are transmitted by the transparent ultrasonic transducer and focused on a preset target area of a sample to be detected, so that the optical scanning and excitation of the sample to be detected are realized, and the photoacoustic signals are converted into electric signals.
5. The handheld multispectral photoacoustic imaging device of claim 1, wherein the data acquisition and control module comprises a data preprocessing unit, a data acquisition unit, and a synchronization control unit; The data preprocessing unit is used for preprocessing the electric signals; the data acquisition unit is used for carrying out analog-to-digital conversion on the preprocessed electric signals to form digital signals; the synchronous control unit is used for receiving the global trigger pulse signal sent by the data acquisition unit and synchronously controlling the multispectral photoacoustic signal excitation module and the MEMS scanning imaging module.
6. The handheld multispectral photoacoustic imaging apparatus of claim 5, wherein the data preprocessing unit comprises a signal amplifier that performs preprocessing of amplitude amplification and signal-to-noise ratio optimization on the electrical signal.
7. The handheld multispectral photoacoustic imaging apparatus of claim 5, wherein the data acquisition unit comprises a data acquisition card and a computer, wherein the data acquisition card performs analog-to-digital conversion of the preprocessed electrical signal to form a digital signal and uploads the digital signal to the computer.
8. The handheld multispectral photoacoustic imaging apparatus of claim 5, wherein the synchronization control unit comprises a field programmable gate array that receives the global trigger pulse signal sent by the data acquisition unit, initiates internal preset synchronization control logic, and synchronously controls the multispectral photoacoustic signal excitation module and the MEMS scanning imaging module according to a preset timing sequence.
9. A multispectral photoacoustic imaging method implemented on the basis of the handheld multispectral photoacoustic imaging apparatus of any one of claims 1-8, the method comprising: In a first laser signal excitation unit, laser output by a first pulse laser sequentially passes through a first linear polarizer and a first half wave plate to carry out polarization regulation and control, is injected into a first polarization maintaining optical fiber by a first optical fiber coupler, generates a broadband laser spectrum through nonlinear optical effect in the first polarization maintaining optical fiber, and after being collimated by a first collimating mirror, selects a first specific wavelength by a first bandpass filter and is guided to a first dichroic mirror by a first reflecting mirror; In the second laser signal excitation unit, laser output by a second pulse laser is divided into two paths through a beam splitter, wherein one path takes the central wavelength of the second pulse laser as a second specific wavelength and is directly output to a second dichroic mirror as fundamental frequency light, the other path is reflected by a second reflecting mirror and sequentially passes through a second linear polarizing plate and a second half-wave plate to carry out polarization regulation and control, a second polarization maintaining optical fiber is injected by a second optical fiber coupler, a broadband laser spectrum is generated through nonlinear optical effect in the second polarization maintaining optical fiber, a third specific wavelength is selected through a second bandpass filter after the second collimating mirror is collimated, and the third specific wavelength is guided to a third dichroic mirror through a third reflecting mirror; the first specific wavelength laser, the second specific wavelength laser and the third specific wavelength laser realize coaxial output through the space beam combination effect of the first dichroic mirror, the second dichroic mirror and the third dichroic mirror, and are coupled into a transmission optical fiber; In the MEMS scanning imaging module, laser of the transmission optical fiber is collimated into parallel beams through a third collimating mirror, the parallel beams are converged through an objective lens and reflected by an MEMS micro-vibrating mirror to realize two-dimensional scanning deflection, the beams are transmitted through a transparent ultrasonic transducer and focused on a preset target area of a sample to be detected, so that optical scanning and excitation of the sample to be detected are realized, and photoacoustic signals are converted into electric signals; in the data acquisition and control module, the electric signals are preprocessed, the preprocessed electric signals are subjected to analog-to-digital conversion to form digital signals, and the multispectral photoacoustic signal excitation module and the MEMS scanning imaging module are synchronously controlled.
10. The method of multispectral photoacoustic imaging of claim 9, wherein the synchronously controlling the multispectral photoacoustic signal excitation module and the MEMS scanning imaging module comprises: And receiving a global trigger pulse signal sent by the data acquisition unit, starting a preset synchronous control logic, and respectively generating and outputting three paths of time sequence control signals according to a preset time sequence, wherein two paths of time sequence control signals are used for driving a first pulse laser and a second pulse laser to emit laser according to a designated frequency and a pulse width, and the other path of time sequence control signals are used for controlling an MEMS micro-vibrating mirror in an MEMS scanning imaging module to execute a preset scanning track.

Description

Handheld multispectral photoacoustic imaging device and method for dry eye detection Technical Field The invention relates to a handheld multispectral photoacoustic imaging device and method for dry eye detection, and belongs to the technical field of medical imaging. Background In recent years, with the popularization of electronic products such as computers and mobile phones, the time for people to use the electronic products is increased, the irradiation time of blue light on a screen is also increased, the number of transient times is reduced, and the number of xerophthalmia patients is increased due to the problems of various factors of the external environment. It is counted that about 30% of the population 50 years and older worldwide is afflicted with dry eye, and the age of dry eye patients tends to younger year by year, and has attracted great attention. Dry eye, a common ocular surface disorder, can cause multidimensional pathophysiological changes in ocular surface tissues, and is mainly characterized by 1) that the dry eye can promote morphological changes of palpebral conjunctival vascular network. Alterations in conjunctival vascular structure are often directly related to eye health problems. Studies have shown alterations in palpebral conjunctival vessel morphology (e.g., diameter and vessel density) and microcirculation (e.g., blood flow rate and blood flow velocity) in dry eye patients. Thus, the assessment of conjunctival microvasculature and microcirculation may provide an indication of the chronic inflammatory state of dry eye, and may further develop into biomarkers of staging and therapeutic efficacy. 2) Dry eye causes abnormal fluctuations in the blood oxygen parameters of the palpebral conjunctiva microcirculation. In the onset of dry eye, the surface of the eye may become dry due to the lack of adequate tear moisturization of the eye, thereby initiating damage to the corneal epithelial cells and inflammatory responses. These changes may affect local oxygen supply, thereby exacerbating dry eye symptoms. This suggests that evaluation of palpebral conjunctival vascular oxygen saturation aids in the detection of dry eye. 3) Meibomian gland dysfunction dry eye can trigger pathological changes in meibomian gland structure. Meibomian glands are the largest sebaceous glands of the human body and are responsible for the synthesis and secretion of the key components of the tear film lipid layer. Meibomian gland dysfunction (Meibomian gland dysfunction, MGD) manifests as meibomian gland obstruction or abnormal meibomian gland secretion, rendering the ocular surface unable to maintain stable tear film, abnormally increased tear evaporation rate, increased tear osmotic pressure, leading to dry eye. MGD typically includes meibomian gland opening, secretion trait, ability to discharge, and abnormal gland structure. It can be seen that the analysis of meibomian gland morphology provides an important basis for dry eye diagnosis, and 4) in addition, MGD-related dry eye patients exhibit significant changes in meibomian gland biomechanical properties. In vivo confocal microscopy showed that periglandular inflammatory cells of MGD patients increased, with increased fibrosis, resulting in decreased glandular elasticity and increased hardness. Therefore, assessing meibomian gland elasticity has important reference value for dry eye diagnosis. With the continued depth of research into dry eye, clinical diagnosis still faces many challenges. Currently mainstream detection methods include dry eye questionnaire, tear film stability detection, tear secretion detection, ophthalmic imaging examination, and the like. Although these methods can detect dry eye to some extent, there are still major limitations, mainly manifested in that firstly, the questionnaire is highly dependent on subjective feelings of patients, which can lead to deviation of results and cannot objectively reflect pathological changes of eyes, secondly, tear film stability detection is insensitive to mild dry eye, operation requirements are high, and is greatly influenced by external factors, tear secretion detection (such as Schirmer test method) is poor in repeatability, ophthalmic imaging examination (such as laser cornea confocal microscope) is limited in imaging range, and lack of quantitative analysis software, and partial examination methods (such as meibomian gland imaging) may not fully reflect functional states of meibomian glands. Researchers at home and abroad make some progress in photoacoustic eye imaging, but mainly focus on improvement and optimization in imaging technology, and have no remarkable progress in clinical transformation, such as portability of an imaging system and solving of clinical problems. Disclosure of Invention The invention aims to solve the defects of the prior art, and provides a handheld multispectral photoacoustic imaging device for dry eye detection, which utilizes multispectral excitation and dynami