Multimodal imaging system and method based on fluorescent nanoprobe and OCT (Optical Coherence Tomography)

Abstract

The invention discloses a multi-modal imaging system and method based on a fluorescent nanoprobe and an OCT (optical coherence tomography), belongs to the technical field of biomedical imaging, and particularly relates to the technical field of analyzing the fluorescent nanoprobe by using an optical means. The multi-mode imaging system comprises a light emitting diode, a dichroscope, a scanning galvanometer, a focusing lens, a sample collector, a fluorescence focusing lens, a photomultiplier, a fluorescence data acquisition unit and a fluorescence nano probe; the system further comprises an SLD broadband spectrum light source, an optical fiber coupler, a collimator, a reflector, a focusing lens, a scanning galvanometer, a dichroscope, a photoelectric detector and an OCT data acquisition unit. The imaging method comprises the following steps: introducing the fluorescent nanoprobe into a biological sample, setting a target area, obtaining an OCT imaging image and a fluorescent imaging image for the target area, and fusing the OCT imaging image and the fluorescent imaging image to obtain a three-dimensional image of the target area. The method is suitable for the fields of tumor early diagnosis, efficacy evaluation, biomedical fundamental research and the like.

Description

Technical Field

[0001] The present invention belongs to the field of medical diagnostic equipment and imaging technology, and specifically relates to a multimodal medical imaging system and method based on heavy metal-free fluorescent nanoprobes and optical coherence tomography (OCT). Background Art

[0002] Cancer, a major global health threat, relies heavily on high-resolution, high-sensitivity imaging technologies for early diagnosis, monitoring of treatment outcomes, and prognostic assessment. Currently, widely used medical imaging modalities include computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), and ultrasound. While these imaging technologies play an important role in visualizing anatomical structures, their molecular resolution is limited, making it difficult to accurately identify small lesions or early tumor markers. Furthermore, some of these technologies (such as CT and PET) involve ionizing radiation, posing potential health risks and high testing costs, making them unsuitable for high-frequency dynamic tracking.

[0003] In recent years, Optical Coherence Tomography (OCT) has attracted widespread attention in the field of biomedical imaging due to its advantages such as high spatial resolution (micrometer level), non-invasiveness, no ionizing radiation, and real-time imaging. It is particularly suitable for high-resolution three-dimensional imaging of shallow tissues and intracavitary structures. OCT reconstructs tissue tomography images by acquiring the backscattered interference signal of near-infrared light in tissues, which can clearly reveal the microstructural changes of tissues. It has been initially applied in fields such as ophthalmology, cardiovascular medicine, and dermatology. However, OCT essentially constructs structural images based on optical scattering characteristics and lacks the ability to identify specific molecules or cell types. It is difficult to provide qualitative and quantitative information at the biomolecular level, which limits its in-depth application in early tumor detection, targeted imaging, and functional imaging.

[0004] Fluorescence imaging, as an important method for molecular imaging, can provide information on the spatial distribution and expression dynamics of target molecules, demonstrating its significant value in molecular biology research and targeted diagnostics. However, traditional fluorescent probes (such as organic dyes and common dyes) suffer from poor photostability, low fluorescence intensity, severe photobleaching, and limited penetration depth. These limitations result in low sensitivity and signal-to-noise ratio for in vivo imaging, hindering the realization of high-resolution dynamic imaging.

[0005] Quantum dots (QDs), emerging fluorescent nanoprobe materials, offer advantages such as high fluorescence quantum yield, strong photostability, tunable emission spectra, and large Stokes shifts. These advantages significantly enhance the sensitivity and spatial resolution of fluorescence imaging. In particular, when doped with functional molecules (such as specific antibodies), quantum dot nanoprobes can achieve highly selective recognition of tumor cells or specific markers, potentially overcoming the technical bottlenecks of traditional fluorescence imaging in terms of targeting and quantification.

[0006] However, there is currently a lack of imaging systems and methods that can effectively integrate the molecular targeting capabilities of quantum dot fluorescent probes with the high-resolution three-dimensional structural imaging capabilities of OCT imaging. This makes specific molecular recognition, spatial localization, and dynamic monitoring in vivo still a significant challenge. In particular, for early detection and real-time tracking of cancer-related molecular markers, existing single-modality imaging systems still face significant trade-offs and technical barriers between sensitivity, resolution, and quantitative capabilities. Summary of the Invention

[0007] To address the technical deficiencies of existing technologies in in vivo target molecule detection, such as insufficient specific recognition capability, limited three-dimensional structural imaging resolution, poor dynamic tracking capability, and poor photostability, this paper proposes a multimodal molecular imaging system and method based on the fusion of heavy metal-free InP / ZnS quantum dot fluorescent nanoprobes and optical coherence tomography (OCT) technology. The specific scheme is as follows: A multimodal imaging system based on fluorescent nanoprobes and OCT, the multimodal imaging system comprising a fluorescence spectrum testing unit, the fluorescence spectrum testing unit comprising: a light emitting diode, for generating an incoherent optical signal and transmitting the incoherent optical signal to a dichroic mirror; A dichroic mirror is used to send light of a target wavelength band in the received optical signal to the scanning galvanometer; A scanning galvanometer is used to spatially deflect the received light of the target wavelength band and send the deflected light beam to the focusing lens; a focusing lens, used for focusing the received deflected light beam onto a collection area of the sample collector; A biological sample injected with fluorescent nanoprobes is placed in the collection area of the sample collector; The focusing lens is further used to receive a fluorescent signal generated by a biological sample and send the fluorescent signal to a scanning galvanometer; The scanning galvanometer is further used to send the received fluorescence signal to the dichroic mirror; The dichroic mirror is further used to send the received fluorescence signal to the fluorescence focusing lens; A fluorescence focusing lens, used to focus the received fluorescence signal to the optical signal input end of the photomultiplier tube; A photomultiplier tube is used to convert the received fluorescence signal into a fluorescent electrical signal, amplify it, and send it to the fluorescence data acquisition unit; The fluorescence data acquisition unit is used to perform analog-to-digital conversion, intensity analysis, image reconstruction and storage on the received fluorescence electrical signals in sequence to obtain fluorescence imaging data.

[0008] Furthermore, the fluorescent nanoprobe is composed of InP / ZnS quantum dots, PEG linking bridge molecules, EpCAM / CD44 mixed antibody targeting molecules and Cy7 near-infrared fluorescent dye; The PEG linking bridge molecule is used to modify the surface of InP / ZnS quantum dots; The EpCAM / CD44 mixed antibody targeting molecule is used to modify the molecular end of the PEG linking bridge molecule; The InP / ZnS quantum dots, PEG link bridge molecules and EpCAM / CD44 mixed antibody targeting molecules are compounded in a Cy7 near-infrared fluorescent dye solution to form a fluorescent nanoprobe.

[0009] Furthermore, the multimodal imaging system further includes an OCT imaging unit, which is: An SLD wide spectrum light source is used to generate a near-infrared coherent optical signal and transmit it to the optical signal input end of the optical fiber coupler; A fiber coupler is used to separate the received infrared coherent light signal into sample light and reference light, and output them separately. The sample light is sequentially transmitted through a dichroic mirror, a scanning galvanometer, and a focusing lens into a collection area in a sample collector, and the reference light is transmitted to the optical signal input end of a collimator. A collimator, used to convert the received reference light into parallel light and then transmit it to the reflector; The reflector is used to reflect the received parallel light along the original path and then inject it into the fiber coupler after passing through the collimator; The focusing lens is further used to receive sample light of the biological sample and transmit it to the scanning galvanometer; The scanning galvanometer is further used to reflect the received sample light of the biological sample to the dichroic mirror; The dichroic mirror is further used to transmit the received sample light of the biological sample to the optical fiber coupler; The optical fiber coupler is further used to superimpose the received sample light of the biological sample and the parallel light to generate an interference light signal, and send the interference light signal to the photosensitive surface of the photodetector; A photodetector, configured to convert the received interference light signal into an interference electrical signal and send it to an OCT data acquisition unit; The OCT data acquisition unit is used to perform high-speed sampling, Fourier transform and depth distribution analysis on the received interference electrical signals in sequence to obtain OCT imaging data.

[0010] Furthermore, the multimodal imaging system further comprises: The display terminal is used to receive the fluorescence imaging data from the fluorescence data acquisition unit, convert it into a fluorescence imaging map and output it, and is also used to receive the OCT imaging data from the OCT data acquisition unit, convert it into an OCT imaging map and output it; A multimodal imaging method based on fluorescent nanoprobes and OCT, the method being implemented based on the multimodal imaging system of claim 3 or 4, the multimodal imaging method comprising: S1, introducing the fluorescent nanoprobe into the biological sample on the sample collector and setting the target area; S2, scanning the target area in real time by the OCT imaging unit to obtain an OCT imaging image; S3, detecting the target area in real time by a fluorescence spectrum testing unit to obtain a fluorescence imaging image; S4. performing spatial registration on the OCT image and the fluorescence image to obtain spatial transformation parameters between the two modal images; S5. Mapping the pixel coordinates of the OCT imaging image and the fluorescence imaging image to the same reference coordinate system according to the spatial transformation parameters to generate fused image data; S6. Perform three-dimensional reconstruction on the fused imaging data to obtain a three-dimensional fused image of the target area.

[0011] Furthermore, the method for obtaining the OCT imaging image described in S2 is: the optical fiber coupler superimposes the received parallel light and the sample light of the biological sample to form an interference light signal, and sends it to the photosensitive surface of the photodetector; the photodetector converts the received interference light into an interference electrical signal, and sends it to the OCT data acquisition unit; the OCT data acquisition unit performs high-speed sampling, Fourier transform and depth distribution analysis on the received interference electrical signal in sequence to obtain OCT imaging data, and obtains the OCT imaging image based on the OCT imaging data.

[0012] Furthermore, the method for obtaining a fluorescence imaging image described in S3 is: the photomultiplier tube converts the received fluorescence signal into a fluorescence electrical signal, amplifies it, and sends it to a fluorescence data acquisition unit, and the fluorescence data acquisition unit performs analog-to-digital conversion, intensity analysis, image reconstruction and storage on the received fluorescence electrical signal in sequence to obtain fluorescence imaging data, and obtains a fluorescence imaging image based on the fluorescence imaging data.

[0013] Furthermore, the method for obtaining the spatial transformation parameters between the two modal images in S4 is: S41, placing a calibration target having a coordinate system and a preset fluorescent marker in a sample collector in sequence, scanning the calibration target using an OCT imaging unit and a fluorescence spectrum testing unit, respectively, to obtain an OCT calibration image and a fluorescence calibration image; S42, detecting geometric corner points or grid intersection points in the OCT calibration image, and detecting corresponding fluorescence point centers in the fluorescence calibration image, to obtain a set of control point pairs between image modalities; S43, calculating a spatial transformation matrix based on the control point pairs using a rigid registration algorithm; S44. Map the voxels in the fluorescence image coordinate system to the OCT image coordinate system using the spatial transformation matrix to obtain spatial transformation parameters between the two modal images.

[0014] Furthermore, the method for generating fused image data in S5 is: S51, using the spatial transformation parameters obtained in step S4, resampling the fluorescence imaging image to the same voxel resolution and grid as the OCT imaging image by interpolation; S52, at each reference voxel position Extract the intensity value in the OCT image And the spectral intensity value in the resampled fluorescence imaging image ; S53, according to the predetermined fusion strategy and Integration, including: Linear weighted fusion: ,in 、 is an adjustable weight; False color overlay: Represented in grayscale or texture, Map to pseudo color channels and then overlay; Multi-channel synthesis: and Assign different output channels respectively to form a multispectral fusion image; S54, the obtained fusion strength value The voxel coordinates are arranged in order to form fused image data.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The multimodal imaging system based on fluorescent nanoprobes and OCT, described in this invention, overcomes the technical bottleneck of existing imaging systems, which suffer from limited functionality and a lack of balanced spatial resolution and molecular specificity, by integrating an InP / ZnS quantum dot fluorescence imaging module with an optical coherence tomography (OCT) structural imaging module. Combining the high fluorescence efficiency of quantum dots with the micron-level resolution of OCT, the device enables the coordinated acquisition of tissue structure and target molecular information on the same platform, significantly improving the spatial correspondence accuracy between molecular imaging and tissue analysis, demonstrating a high level of system integration and clinical applicability.

[0016] 2. The multimodal imaging system based on fluorescent nanoprobes and OCT described in this invention utilizes a coaxial confocal optical path design to achieve spatial fusion of fluorescence excitation, scattered signal acquisition, and OCT interferometric imaging optical paths. This reduces the impact of optical path alignment errors on image registration accuracy and improves the stability and imaging consistency of multimodal image superposition. Compared to the prior art method of using separate fluorescence imaging and structural imaging devices for post-image synthesis, this device can complete imaging within the same time window, possessing stronger real-time dynamic monitoring capabilities and spatial reference accuracy, providing strong support for the precise detection and tracking of tiny lesions.

[0017] 3. The multimodal imaging method based on fluorescent nanoprobes and OCT described in this invention first uses functionally modified InP / ZnS quantum dot fluorescent nanoprobes to bind with target molecules with high affinity. Then, an integrated device is used to perform fluorescence excitation and OCT scanning imaging of the sample area, achieving simultaneous acquisition and fusion imaging of molecular signals and tissue structures. This method effectively addresses the spatiotemporal asynchrony between fluorescence signals and tissue structure images in traditional imaging methods, enabling real-time correlation of molecular behavior during dynamic processes with their structural context, thereby improving the timeliness and interpretability of imaging data.

[0018] 4. The multimodal imaging method based on fluorescent nanoprobes and OCT, described in this invention, leverages the high signal-to-noise ratio and photobleaching resistance of quantum dot fluorescence signals to achieve long-term, high-frequency imaging acquisition during molecular tracking, avoiding the signal instability associated with the rapid attenuation of traditional fluorescent probes under continuous illumination. Furthermore, combined with the high-resolution structural information acquired by OCT, image shifts caused by factors such as tissue movement and imaging angle changes can be corrected in real time, significantly improving the comparability and analytical accuracy of multi-timepoint images. This method is suitable for in vivo dynamic observation of biological processes such as molecular diffusion and cell migration.

[0019] 5. The multimodal imaging method based on fluorescent nanoprobes and OCT described in this paper offers significant advantages in its biocompatibility and environmental adaptability. It can be adapted to a variety of animal models and tissue types, and the excitation wavelength, image fusion algorithm, and data post-processing strategy can be flexibly adjusted according to target needs. It exhibits high scalability and application flexibility, surpassing traditional methods in their adaptability to multiple scenarios and molecular targets.

[0020] The multimodal imaging system and method based on fluorescent nanoprobes and OCT described in the present invention are applicable to medical diagnostic technology fields such as oncology diagnosis, minimally invasive surgical navigation, dynamic evaluation of drug efficacy, and applications in ophthalmology and dermatology. The present invention achieves high-resolution three-dimensional positioning and real-time functional imaging of specific molecular markers in biological tissues by coupling fluorescent molecular imaging and OCT structural imaging technology, and is also applicable to clinical scenarios such as early cancer screening, intraoperative navigation, and efficacy evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the principle of a fluorescent nanoprobe and OCT multimodal imaging system described in embodiment 1, with the following reference numerals: light-emitting diode 6, dichroic mirror 7, scanning galvanometer 8, focusing lens 9, sample collector 10, fluorescence focusing lens 11, photomultiplier tube 12, fluorescence data acquisition unit 13, SLD wide-spectrum light source 14, fiber coupler 15, collimator 16, reflector 17, photodetector 18, OCT data acquisition unit 19, display terminal 20.

[0022] Figure 2 This is a schematic diagram of the synthesis scheme of the fluorescent nanoprobe described in the tenth embodiment, with the accompanying symbols: InP / ZnS quantum dots 1, PEG link bridge molecule 2, EpCAM / CD44 mixed antibody targeting molecule 3, Cy7 near-infrared fluorescent dye 4, and fluorescent nanoprobe 5. DETAILED DESCRIPTION

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0024] Implementation Method 1 like Figure 1 As shown, a multimodal imaging system based on fluorescent nanoprobes and OCT, the multimodal imaging system includes a fluorescence spectrum testing unit, the fluorescence spectrum testing unit includes: A light emitting diode 6 is used to generate an incoherent light signal and transmit it to a dichroic mirror 7; A dichroic mirror 7 is used to send the light of the target wavelength band in the received optical signal to the scanning galvanometer 8; The scanning galvanometer 8 is used to spatially deflect the received light of the target wavelength band and send the deflected light beam to the focusing lens 9; A focusing lens 9 is used to focus the received deflected light beam onto a collection area of a sample collector 10; The collection area of the sample collector 10 is coated with a biological sample injected with fluorescent nanoprobes 5; The focusing lens 9 is further used to receive the fluorescent signal generated by the biological sample and send the fluorescent signal to the scanning galvanometer 8; The scanning galvanometer 8 is also used to send the received fluorescence signal to the dichroic mirror 7; The dichroic mirror 7 is also used to send the received fluorescence signal to the fluorescence focusing lens 11; The fluorescence focusing lens 11 is used to focus the received fluorescence signal to the optical signal input end of the photomultiplier tube 12; The photomultiplier tube 12 is used to convert the received fluorescent signal into a fluorescent electrical signal, amplify it, and send it to the fluorescent data acquisition unit 13; The fluorescence data acquisition unit 13 is used to perform analog-to-digital conversion, intensity analysis, image reconstruction and storage on the received fluorescence electrical signal in sequence to obtain fluorescence imaging data.

[0025] This embodiment constructs a multimodal imaging system that combines fluorescent nanoprobes with OCT technology, achieving the linked acquisition of incoherent light and fluorescent signals, effectively improving the sensitivity and resolution of the imaging system. The device adopts a multi-level optical path design, which can perform high-precision spatial scanning of the target area and fluorescence excitation and collection. It is suitable for multidimensional imaging of biological tissues and precise detection of specific markers. The multimodal imaging system described in this embodiment has a compact overall structure and high integration, which is conducive to deployment and use in clinical and laboratory environments, and provides technical support for disease diagnosis, cell research and in vivo imaging.

[0026] Implementation Method 2 This embodiment is a further limitation of the first embodiment. In this embodiment, the fluorescent nanoprobe 5 is composed of InP / ZnS quantum dots 1, PEG linker molecules 2, EpCAM / CD44 mixed antibody targeting molecules 3 and Cy7 near-infrared fluorescent dye 4; The PEG link bridge molecule 2 is used to modify the surface of the InP / ZnS quantum dot 1; The EpCAM / CD44 mixed antibody targeting molecule 3 is used to modify the molecular end of the PEG link bridge molecule 2; The InP / ZnS quantum dots 1, PEG link bridge molecules 2 and EpCAM / CD44 mixed antibody targeting molecules 3 are compounded in a Cy7 near-infrared fluorescent dye 4 solution to form a fluorescent nanoprobe 5.

[0027] This embodiment optimizes the composition and structure of the fluorescent nanoprobe, incorporating InP / ZnS quantum dots as the fluorescent core, combined with a PEG bridge for water solubility and stability, using a hybrid EpCAM / CD44 antibody to impart targeted recognition, and combining it with a Cy7 near-infrared fluorescent dye to enhance penetration depth and signal-to-noise ratio. This fluorescent nanoprobe boasts high fluorescence quantum yield, good biocompatibility, and strong targeting capabilities. It achieves stable imaging signal output in complex biological environments, effectively improving imaging specificity and molecular detection capabilities.

[0028] Implementation Method 3 This embodiment is a further limitation of the first embodiment. In this embodiment, the multimodal imaging system further includes an OCT imaging unit. The OCT imaging unit is: The SLD wide spectrum light source 14 is used to generate a near-infrared coherent optical signal and transmit it to the optical signal input end of the optical fiber coupler 15; The fiber coupler 15 is used to separate the received infrared coherent light signal into sample light and reference light, and output them separately. The sample light is sequentially transmitted through the dichroic mirror 7, the scanning galvanometer 8 and the focusing lens 9 into the collection area of the sample collector 10, and the reference light is transmitted to the optical signal input end of the collimator 16; The collimator 16 is used to convert the received reference light into parallel light and then transmit it to the reflector 17; The reflector 17 is used to reflect the received parallel light along the original path and inject it into the fiber coupler 15 after passing through the collimator 16; The focusing lens 9 is also used to receive the sample light of the biological sample and transmit it to the scanning galvanometer 8; The scanning galvanometer 8 is further used to reflect the sample light of the received biological sample to the dichroic mirror 7; The dichroic mirror 7 is also used to transmit the received sample light of the biological sample to the optical fiber coupler 15; The optical fiber coupler 15 is also used to superimpose the sample light of the received biological sample and the parallel light to generate an interference light signal, and send it to the photosensitive surface of the photodetector 18; The photodetector 18 is used to convert the received interference light signal into an interference electrical signal and send it to the OCT data acquisition unit 19; The OCT data acquisition unit 19 is used to perform high-speed sampling, Fourier transform, and depth distribution analysis on the received interference electrical signal in sequence to obtain OCT imaging data.

[0029] This implementation integrates near-infrared OCT imaging with fluorescence imaging by introducing an SLD wide-spectrum light source and an optical interferometer module into the existing imaging system. This device enables tomographic imaging of sample structure information, capturing the microscopic depth distribution characteristics of tissues, complementing fluorescence imaging and meeting the needs of multimodal imaging. The introduction of the OCT module improves the system's structural imaging accuracy, enabling simultaneous acquisition of sample information at different scales, enhancing the system's applicability and scalability in applications such as medical diagnosis, tissue analysis, and drug imaging.

[0030] Implementation Method 4 This embodiment further limits the third embodiment. In this embodiment, the multimodal imaging system further includes: The display terminal 20 is used to receive the fluorescence imaging data from the fluorescence data acquisition unit 13, convert it into a fluorescence imaging map, and output it; it is also used to receive the OCT imaging data from the OCT data acquisition unit 19, convert it into an OCT imaging map, and output it; This embodiment incorporates a display terminal into the multimodal imaging system, enabling real-time visualization of image data. By receiving data transmitted by the fluorescence data acquisition unit and the OCT data acquisition unit, respectively, the terminal can synchronously display the fluorescence imaging image and the OCT structural image, providing the user with a clear and intuitive image observation interface. The display terminal supports multimodal image comparison and analysis functions, facilitating target area identification, lesion localization, and imaging result comparison by doctors or researchers, improving data interpretation efficiency and enhancing the system's application value in real-time monitoring, intraoperative navigation, and scientific research and teaching.

[0031] The specific technical means further described in the above-mentioned embodiments 2 to 4 can also be reasonably combined with each other to form new embodiments.

[0032] Implementation Method Five A multimodal imaging method based on fluorescent nanoprobes and OCT, the method being implemented based on the multimodal imaging system described in any one of the above embodiments, the method comprising: S1, introducing the fluorescent nanoprobe into the biological sample on the sample collector 10 and setting the target area; S2, scanning the target area in real time by the OCT imaging unit to obtain an OCT imaging image; S3, detecting the target area in real time by a fluorescence spectrum testing unit to obtain a fluorescence imaging image; S4. performing spatial registration on the OCT image and the fluorescence image to obtain spatial transformation parameters between the two modal images; S5. Mapping the pixel coordinates of the OCT imaging image and the fluorescence imaging image to the same reference coordinate system according to the spatial transformation parameters to generate fused image data; S6. Perform three-dimensional reconstruction on the fused imaging data to obtain a three-dimensional fused image of the target area.

[0033] This embodiment provides a complete method flow for integrating OCT and fluorescence imaging. By acquiring and processing multimodal information, it achieves the simultaneous presentation of structural and functional information of the target region of a biological sample. This method not only obtains OCT tissue structural images, but also generates functional images by acquiring fluorescence signals in real time. Furthermore, through a registration algorithm, spatial image fusion is achieved, generating three-dimensional imaging results in a unified reference frame. The overall process boasts strong systematicity, rich information dimensions, and high reconstruction accuracy, providing a more comprehensive technical approach for the comprehensive assessment of complex tissue lesions and targeted treatment strategies.

[0034] Implementation Method 6 This embodiment is a further limitation of embodiment one. In this embodiment, the method for obtaining the OCT imaging image described in S2 is: the optical fiber coupler 15 superimposes the received parallel light and the sample light of the biological sample to form an interference light signal, and sends it to the photosensitive surface of the photodetector 18; the photodetector 18 converts the received interference light into an interference electrical signal, and sends it to the OCT data acquisition unit 19; the OCT data acquisition unit 19 performs high-speed sampling, Fourier transform and depth distribution analysis on the received interference electrical signal in sequence to obtain OCT imaging data, and obtains an OCT imaging image based on the OCT imaging data.

[0035] This implementation clearly defines the OCT image acquisition process. By collecting and Fourier transforming interferometric light signals, it enables layered scanning and in-depth reconstruction of tissue microstructures. The photodetector, used in conjunction with the OCT data acquisition unit, enables high-speed sampling and efficient processing of interferometric electrical signals, ensuring the accuracy and timeliness of imaging data. This method is particularly well-suited for resolving and identifying tissue microstructures, helping to accurately capture subtle structural changes within samples, and possesses significant practical value in early disease diagnosis and tissue engineering research.

[0036] Implementation Method Seven This embodiment is a further limitation of embodiment one. In this embodiment, the method for obtaining a fluorescence imaging image described in S3 is: the photomultiplier tube 12 converts the received fluorescence signal into a fluorescence electrical signal, amplifies the signal, and sends the signal to the fluorescence data acquisition unit 13. The fluorescence data acquisition unit 13 performs analog-to-digital conversion, intensity analysis, image reconstruction, and storage on the received fluorescence electrical signal in sequence to obtain fluorescence imaging data, and obtains a fluorescence imaging image based on the fluorescence imaging data.

[0037] This implementation details the process and key technologies for acquiring fluorescence images. Photomultiplier tubes (PMTs) receive and amplify fluorescence signals with high sensitivity, and a fluorescence data acquisition unit performs analog-to-digital conversion, image reconstruction, and data storage, ensuring image quality and signal fidelity. This solution offers the advantages of high signal processing accuracy and robust image reproduction, enabling efficient capture of weak fluorescence signals and meeting the needs of targeted molecular-level detection. It is particularly suitable for labeling trace biomarkers or cellular targets, enabling intuitive visualization of molecular distribution.

[0038] Implementation Method Eight This embodiment is a further limitation of the first embodiment. In this embodiment, the method for obtaining the spatial transformation parameters between the two modal images in step S4 is: S4.1. Place a calibration target having a coordinate system and a preset fluorescent marker in the sample collector 10 in sequence, and scan the calibration target using the OCT imaging unit and the fluorescence spectrum testing unit, respectively, to obtain an OCT calibration image and a fluorescence calibration image; S4.2. Detecting geometric corner points or grid intersections in the OCT calibration image and detecting corresponding fluorescence spot centers in the fluorescence calibration image to obtain a set of control point pairs between the image modalities; S4.3. Calculate a spatial transformation matrix based on the control point pairs using a rigid registration algorithm; S4.4. Use the spatial transformation matrix to map the voxels in the fluorescence image coordinate system to the OCT image coordinate system to obtain the spatial transformation parameters between the two modality images.

[0039] This implementation effectively acquires spatial transformation parameters between OCT and fluorescence images by introducing a calibration target with coordinate references and pre-defined markers, utilizing image control point detection and a rigid registration algorithm. This registration strategy improves the spatial consistency of multimodal images and resolves geometric deviations between different imaging modalities. By establishing control point pairs and calculating a registration matrix, high-precision image coordinate mapping is achieved, laying a solid foundation for subsequent image fusion and 3D reconstruction, ensuring the accuracy of spatial positioning and target alignment in the fused image.

[0040] Implementation Method Nine This embodiment is a further limitation of the first embodiment. In this embodiment, the method for generating fused image data in step S5 is: S51, using the spatial transformation parameters obtained in step S4, resampling the fluorescence imaging image to the same voxel resolution and grid as the OCT imaging image by interpolation; S52, at each reference voxel position Extract the intensity value in the OCT image And the spectral intensity value in the resampled fluorescence imaging image ; S53, according to the predetermined fusion strategy and Integration, including: Linear weighted fusion: ,in 、 is an adjustable weight; False color overlay: Represented in grayscale or texture, Map to pseudo color channels and then overlay; Multi-channel synthesis: and Assign different output channels respectively to form a multispectral fusion image; S54, the obtained fusion strength value The voxel coordinates are arranged in order to form fused image data.

[0041] Furthermore, step S5.1 aims to map the voxels of the fluorescence image onto the voxel grid of the OCT image by aligning the coordinate system of the fluorescence image with the coordinate system of the OCT image. At this point, the position of each voxel has been redefined spatially, so that the two modal images have consistent voxel resolution and spatial position in the same spatial coordinate system.

[0042] Furthermore, the reference voxel position described in step S5.2 Refers to the spatial location of each voxel in the fused image, corresponding to the intersection of a voxel in the OCT image and a voxel in the resampled fluorescence image. These voxels, taken as a whole, represent the data set for each volumetric element in the image and are used for subsequent fusion of the OCT and fluorescence images.

[0043] This implementation incorporates in-depth design of image fusion technology, proposing various fusion strategies, including linear weighting, pseudocolor overlay, and multi-channel synthesis, to effectively integrate the intensity information and spectral characteristics of OCT and fluorescence imaging. By fusing pixel-level data and unifying them into a common voxel coordinate system, the resulting 3D fused image preserves the detailed features of tissue structure while enhancing the expression of functional signals. This approach facilitates the collaborative interpretation of multidimensional information, improving the comprehensive image description of tissue lesions, molecular expression, and spatial location.

[0044] The specific technical means further described in the above embodiments 6 to 9 can also be reasonably combined with each other to form new embodiments.

[0045] Implementation Method 10 like Figure 2 As shown, a schematic diagram of the synthesis scheme of the fluorescent nanoprobe 5 described in this embodiment is provided. The synthesis method of the fluorescent nanoprobe 5 is as follows: first, InP / ZnS quantum dots 1, PEG link bridge molecules 2, and EpCAM / CD44 mixed antibody targeting molecules 3 are mixed in a deionized water solution, and the PEG link bridge molecules 2 and EpCAM / CD44 mixed antibody targeting molecules 3 are modified to the surface of the InP / ZnS quantum dots 1, and then compounded in a Cy7 near-infrared fluorescent dye 4 solution to finally synthesize the fluorescent nanoprobe 5.

[0046] Quantum dots commonly used in existing fluorescent nanoprobes, such as CdSe / ZnS and PbS, contain heavy metal elements, and their potential biotoxicity and environmental hazards limit their further application in biomedicine.

[0047] The fluorescent nanoprobes in this embodiment are made of indium phosphide (InP) quantum dots. As a new heavy metal-free fluorescent probe material, InP quantum dots combine low toxicity, excellent optical properties, and biocompatibility. This overcomes the high biotoxicity of traditional fluorescent probes, meets biosafety requirements, and is more suitable for biomedical applications. Furthermore, their emission wavelength can be adjusted to the near-infrared (NIR) region, providing enhanced tissue penetration depth and reduced background signal interference. Their optical properties exhibit high stability and quantum yield. The fluorescent nanoprobes in this embodiment, combined with OCT imaging technology, achieve molecular and structural dual-modality imaging results with excellent tissue penetration depth and molecular localization accuracy, demonstrating significant innovation in technological integration and functional synergy.

[0048] Implementation Method Eleven This embodiment integrates the technical solutions described in the aforementioned multiple embodiments, combines actual application scenarios and the use process of the computer program product that implements the method described in the present invention, and further verifies and explains the technical effects of the present invention through specific examples.

[0049] A multimodal imaging method based on fluorescent nanoprobes and OCT, the method comprising the following steps: Step 1. Introduce the synthesized quantum dot fluorescent nanoprobe into the biological sample and use the incoherent light source of the light-emitting diode to illuminate the target area to induce the quantum dot fluorescent nanoprobe; Step 2. Scan the target area using the OCT imaging unit to obtain OCT tomographic image data; Step 3. Based on the OCT imaging unit, a fluorescence spectroscopy test unit is added to the sample arm optical path of the OCT system; Step 4. Using the fluorescence spectroscopy testing unit, fluorescence detection is performed simultaneously with OCT scanning. The light source excites the fluorescent nanoprobe, and energy is transferred to the target molecule to generate a fluorescent signal. The fluorescence is reflected to the photomultiplier tube, and fluorescence spectral image data is further obtained. Step 5. The scanning galvanometer in the OCT imaging unit simultaneously controls the light position of the fluorescence spectrum testing unit. The scanning galvanometer synchronously controls the scanning process of the system OCT and fluorescence imaging units. Step 6. In the photodetector, the data acquisition card converts the interference signal collected by the OCT in real time and transmits it to the computer for data processing to obtain the depth encoding signal. The specific OCT data processing is as follows: a) Spectral shaping. To reduce noise in the captured image, the interference spectrum needs to be shaped. Using a window function, the interference spectrum signal is apodized before Fourier transform to suppress interference images introduced by sidelobes and achieve optimal image contrast.

[0050] b) Dispersion compensation and Fourier transform. To reduce the change in pulse shape caused by dispersion, a phase offset is introduced by software and expanded by Taylor series: , in, represents the wave number, represents the central wave number, represents the interference phase term, Represents the center wave number The phase constant value at Representatives in Place Taking the first derivative, Representatives in Place The second derivative is Representatives in Place The highest order derivative taken.

[0051] c) Image reconstruction. The acquired lateral and axial spatial signals are reconstructed. The lateral dimension is determined using the geometric optical parameters of the sample scanning optical system and the scanning angle. The axial dimension is calculated using the detection depth formula. In this patent, the axial imaging is divided by the refractive index of the target biological region to obtain the true depth of the biological sample.

[0052] d) Using the target molecules in the cancer cells to obtain the fluorescence emitted by the fluorescent nanoprobe, the position of the target molecules is tracked in real time, and the OCT galvanometer is used to scan the area at that position. The above steps are synchronized to achieve real-time tracking while accurately observing the imaging of the target area.

[0053] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0054] like Figure 1 As shown, the OCT functional imaging principle of this embodiment is as follows: a fluorescent nanoprobe 5 is injected into the sample, and a light-emitting diode 6 emits an incoherent light signal, which is reflected by a dichroic mirror 7 and a scanning galvanometer 8 and then focused on the sample by a focusing lens 9. The fluorescent nanoprobe 5 is excited to emit fluorescence, which passes through the dichroic mirror 7 and a fluorescence focusing lens 11 and enters a photomultiplier tube 12. The photomultiplier tube 12 analyzes the fluorescence information and reconstructs a fluorescence image in a fluorescence data acquisition unit 13. Simultaneously, an SLD wide-spectrum light source 14 emits a near-infrared coherent light signal, which is output to the sample arm and reference arm via the two output ends of a fiber coupler 15, respectively. The output end of the sample arm is connected to the dichroic mirror 7. The sample light passes through the dichroic mirror 7, is reflected by the scanning galvanometer 8, and finally illuminates the sample through the focusing lens 9. The sample light then returns to the fiber coupler 15 along the same path. The output fiber connector of the sample arm is connected to a collimator 16. The reference light passes through the collimator and outputs parallel light, which illuminates a reflector 17 and then returns to the fiber coupler 15 along the same path. The sample light and reference light interfere in the fiber coupler, and the resulting interference is input from the other end of the fiber coupler 15 into the photodetector 18 for processing. Leveraging the ability of near-infrared light to penetrate skin tissue, the OCT system of the present invention can obtain tomographic images at different depths and locations within the sample, performing deep-range structural imaging of the target cancer cell region and observing depth-level information. Furthermore, the efficient combination of fluorescent nanoprobes, fluorescence spectroscopy testing units, and OCT imaging units enables accurate, sensitive, and real-time detection of specific target molecules and regions.

[0055] The technical solution provided by the present invention is further described in detail through the above specific embodiments in order to highlight the advantages and benefits of the technical solution provided by the present invention. However, the above specific embodiments are not intended to limit the present invention. Any reasonable modification and improvement of the present invention, combination of embodiments and equivalent replacement, etc. based on the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0056] Those skilled in the art will understand that the above description is only a preferred embodiment of the present invention, and the various embodiments disclosed in the present invention and / or the features described in the claims can be combined or coupled in various ways, even if such combinations or couplings are not explicitly described in the disclosure of the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0057] Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, the present invention is intended to include such changes and modifications as fall within the scope of the claims and their equivalents.

Claims

1. A multimodal imaging system based on fluorescent nanoprobes and OCT, characterized in that: The multimodal imaging system includes a fluorescence spectrum testing unit, and the fluorescence spectrum testing unit includes: A light emitting diode (6) for generating an incoherent light signal and transmitting the signal to a dichroic mirror (7); A dichroic mirror (7) is used to send light of a target wavelength band in the received optical signal to a scanning galvanometer (8); A scanning galvanometer (8) is used to spatially deflect the received light of a target wavelength band and send the deflected light beam to a focusing lens (9); A focusing lens (9) is used to focus the received deflected light beam onto a collection area of a sample collector (10); A biological sample injected with a fluorescent nanoprobe (5) is placed in a collection area of the sample collector (10); The focusing lens (9) is also used to receive the fluorescent signal generated by the biological sample and send the fluorescent signal to the scanning galvanometer (8); The scanning galvanometer (8) is also used to send the received fluorescence signal to the dichroic mirror (7); The dichroic mirror (7) is further used to send the received fluorescence signal to the fluorescence focusing lens (11); A fluorescence focusing lens (11) is used to focus the received fluorescence signal onto the optical signal input end of the photomultiplier tube (12); A photomultiplier tube (12) is used to convert the received fluorescence signal into a fluorescence electrical signal, amplify the signal, and send the signal to a fluorescence data acquisition unit (13); The fluorescence data acquisition unit (13) is used to sequentially perform analog-to-digital conversion, intensity analysis, image reconstruction and storage on the received fluorescence electrical signal to obtain fluorescence imaging data.

2. The multimodal imaging system according to claim 1, wherein: The fluorescent nanoprobe (5) is composed of InP / ZnS quantum dots (1), PEG linking bridge molecules (2), EpCAM / CD44 mixed antibody targeting molecules (3) and Cy7 near-infrared fluorescent dye (4); The PEG linking bridge molecule (2) is used to modify the surface of the InP / ZnS quantum dots (1); The EpCAM / CD44 mixed antibody targeting molecule (3) is used to modify the molecular end of the PEG linking bridge molecule (2); The InP / ZnS quantum dots (1), PEG link bridge molecules (2) and EpCAM / CD44 mixed antibody targeting molecules (3) are compounded in a Cy7 near-infrared fluorescent dye (4) solution to form a fluorescent nanoprobe (5).

3. The multimodal imaging system according to claim 1, wherein: The multimodal imaging system further includes an OCT imaging unit, which is: An SLD wide spectrum light source (14) is used to generate a near-infrared coherent optical signal and transmit it to an optical signal input end of a fiber coupler (15); The optical fiber coupler (15) is used to separate the received infrared coherent light signal into sample light and reference light, and output them separately, wherein the sample light is sequentially transmitted through the dichroic mirror (7), the scanning galvanometer (8) and the focusing lens (9) into the collection area of the sample collector (10), and the reference light is transmitted to the optical signal input end of the collimator (16); A collimator (16) is used to convert the received reference light into parallel light and then transmit it to the reflector (17); A reflector (17) is used to reflect the received parallel light along the original path and inject it into the optical fiber coupler (15) after passing through the collimator (16); The focusing lens (9) is also used to receive sample light of the biological sample and transmit it to the scanning galvanometer (8); The scanning galvanometer (8) is further used to reflect the received sample light of the biological sample to the dichroic mirror (7); The dichroic mirror (7) is further used to transmit the received sample light of the biological sample to the optical fiber coupler (15); The optical fiber coupler (15) is further used to superimpose the received sample light of the biological sample and the parallel light to generate an interference light signal, and send the interference light signal to the photosensitive surface of the photodetector (18); The photodetector (18) is used to convert the received interference light signal into an interference electrical signal and send it to the OCT data acquisition unit (19); The OCT data acquisition unit (19) is used to sequentially perform high-speed sampling, Fourier transform, and depth distribution analysis on the received interference electrical signal to obtain OCT imaging data.

4. The multimodal imaging system according to claim 3, wherein: The multimodal imaging system further comprises: The display terminal (20) is used to receive the fluorescence imaging data from the fluorescence data acquisition unit (13), convert it into a fluorescence imaging map and output it, and is also used to receive the OCT imaging data from the OCT data acquisition unit (19), convert it into an OCT imaging map and output it.

5. A multimodal imaging method based on fluorescent nanoprobes and OCT, characterized in that: The method is implemented based on the multimodal imaging system according to claim 3 or 4, and the multimodal imaging method includes: S1, introducing the fluorescent nanoprobe into the biological sample on the sample collector (10) and setting the target area; S2, scanning the target area in real time by the OCT imaging unit to obtain an OCT imaging image; S3, detecting the target area in real time by a fluorescence spectrum testing unit to obtain a fluorescence imaging image; S4. performing spatial registration on the OCT image and the fluorescence image to obtain spatial transformation parameters between the two modal images; S5. Mapping the pixel coordinates of the OCT imaging image and the fluorescence imaging image to the same reference coordinate system according to the spatial transformation parameters to generate fused image data; S6. Perform three-dimensional reconstruction on the fused imaging data to obtain a three-dimensional fused image of the target area.

6. The multimodal imaging method according to claim 5, characterized in that: The method for obtaining the OCT imaging image described in S2 is: the optical fiber coupler (15) superimposes the received parallel light and the sample light of the biological sample to form an interference light signal, and sends it to the photosensitive surface of the photodetector (18); the photodetector (18) converts the received interference light into an interference electrical signal, and sends it to the OCT data acquisition unit (19); the OCT data acquisition unit (19) sequentially performs high-speed sampling, Fourier transformation and depth distribution analysis on the received interference electrical signal to obtain OCT imaging data, and obtains an OCT imaging image based on the OCT imaging data.

7. The multimodal imaging method according to claim 5, wherein: The method for obtaining the fluorescence imaging image described in S3 is as follows: the photomultiplier tube (12) converts the received fluorescence signal into a fluorescence electrical signal, amplifies the signal, and sends the signal to the fluorescence data acquisition unit (13); the fluorescence data acquisition unit (13) sequentially performs analog-to-digital conversion, intensity analysis, image reconstruction, and storage on the received fluorescence electrical signal to obtain fluorescence imaging data, and obtains a fluorescence imaging image based on the fluorescence imaging data.

8. The multimodal imaging method according to claim 5, wherein: The method for obtaining the spatial transformation parameters between the two modal images in S4 is: S41, placing a calibration target having a coordinate system and a preset fluorescent marker in the sample collector (10) in sequence, and scanning the calibration target using an OCT imaging unit and a fluorescence spectrum testing unit, respectively, to obtain an OCT calibration image and a fluorescence calibration image; S42, detecting geometric corner points or grid intersection points in the OCT calibration image, and detecting corresponding fluorescence point centers in the fluorescence calibration image, to obtain a set of control point pairs between image modalities; S43, calculating a spatial transformation matrix based on the control point pairs using a rigid registration algorithm; S44. Map the voxels in the fluorescence image coordinate system to the OCT image coordinate system using the spatial transformation matrix to obtain spatial transformation parameters between the two modal images.

9. The multimodal imaging method according to claim 5, wherein: The method for generating fused image data in S5 is: S51, using the spatial transformation parameters obtained in step S4, resampling the fluorescence imaging image to the same voxel resolution and grid as the OCT imaging image by interpolation; S52, at each reference voxel position Extract the intensity value in the OCT image And the spectral intensity value in the resampled fluorescence imaging image ; S53, according to the predetermined fusion strategy and Integration, including: Linear weighted fusion: ,in 、 is an adjustable weight; Pseudo color overlay: Represented in grayscale or texture, Map to pseudo color channels and then overlay; Multi-channel synthesis: and Assign different output channels respectively to form a multispectral fusion image; S54, the obtained fusion strength value The voxel coordinates are arranged in order to form fused image data.

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