Spinal cord injury is a severe neurological disorder;however,current treatment methods often fail to restore nerve function effectively.Spinal cord stimulation via electrical signals is a promising therapeutic modalit...Spinal cord injury is a severe neurological disorder;however,current treatment methods often fail to restore nerve function effectively.Spinal cord stimulation via electrical signals is a promising therapeutic modality for spinal cord injury.Based on similar principles,this review aims to explore the potential of optical and acoustic neuromodulation techniques,emphasizing their benefits in the context of spinal cord injury.Photoacoustic imaging,renowned for its noninvasive nature,high-resolution capabilities,and cost-effectiveness,is well recognized for its role in early diagnosis,dynamic monitoring,and surgical guidance in stem cell therapies for spinal cord injury.Moreover,photoacoustodynamic therapy offers multiple pathways for tissue regeneration.Optogenetics and sonogenetics use genetic engineering to achieve precise neuronal activation,while photoacoustoelectric therapy leverages photovoltaic materials for electrical modulation of the nervous system,introducing an innovative paradigm for nerve system disorder management.Collectively,these advancements represent a transformative shift in the diagnosis and treatment of spinal cord injury,with the potential to significantly enhance nerve function remodeling and improve patient outcomes.展开更多
To investigate the mechanisms underlying the onset and progression of ischemic stroke,some methods have been proposed that can simultaneously monitor and create embolisms in the animal cerebral cortex.However,these me...To investigate the mechanisms underlying the onset and progression of ischemic stroke,some methods have been proposed that can simultaneously monitor and create embolisms in the animal cerebral cortex.However,these methods often require complex systems and the effect of age on cerebral embolism has not been adequately studied,although ischemic stroke is strongly age-related.In this study,we propose an optical-resolution photoacoustic microscopy-based visualized photothrombosis methodology to create and monitor ischemic stroke in mice simultaneously using a 532 nm pulsed laser.We observed the molding process in mice of different ages and presented age-dependent vascular embolism differentiation.Moreover,we integrated optical coherence tomography angiography to investigate age-associated trends in cerebrovascular variability following a stroke.Our imaging data and quantitative analyses underscore the differential cerebrovascular responses to stroke in mice of different ages,thereby highlighting the technique's potential for evaluating cerebrovascular health and unraveling age-related mechanisms involved in ischemic strokes.展开更多
We theoretically investigate the feasibility of reconstructing the transverse structures of femtosecond laser filaments in air by photoacoustic tomography.To simulate the emission and transmission of filament-induced ...We theoretically investigate the feasibility of reconstructing the transverse structures of femtosecond laser filaments in air by photoacoustic tomography.To simulate the emission and transmission of filament-induced ultrasonic signals more truly,a series of experimentally recorded cross-sectional images are used to simulate the initial pressure rise from multiple filaments(MFs).The aperture size and sensitivity of the detector was incorporated into the reconstruction algorithm.The results show that frequency of acoustic signals induced by MFs with maximum volumetric energy density~100 k J/m^(3)is about 2 MHz below.The initial spatial distribution of optical filaments can be clearly reconstructed with the back projection based algorithm.We recommend a PAT system with transducers of a lower central frequency and a stronger apodization working at a longer scanning radius can be used in photoacoustic image reconstruction of femtosecond laser multifilaments.This study demonstrates the feasibility of using photoacoustic tomography to reconstruct femtosecond multifilament images,which is helpful for studying the complex dynamic processes of multifilament and multifilament manipulation and is also valuable for the remote applications of laser filaments.展开更多
The temperature of an organism provides key insights into its physiological and pathological status.Temperature monitoring can effectively assess potential health issues and plays a critical role in thermal treatment....The temperature of an organism provides key insights into its physiological and pathological status.Temperature monitoring can effectively assess potential health issues and plays a critical role in thermal treatment.Photoacoustic imaging(PAI)has enabled multi-scale imaging,from cells to tissues and organs,where its high contrast,deep penetration,and high resolution make it an emerging tool in biomedical imaging field.Benefiting from the linear correlation between the Grüneisen parameter and temperature within the range of 10–55∘C,the PAI has been developed as novel noninvasive label-free tool for temperature monitoring especially for thermotherapy mediated by laser,ultrasound,and microwave.Additionally,by utilizing temperature-responsive photoacoustic nanoprobes,the temperature information of the targeted organism can also be extracted with enhanced imaging contrast and specificity.This review elucidates the basic principles of temperature monitoring technology implemented by PAI,further highlighting the limitations of traditional photoacoustic thermometry,and summarizes recent technological advancements in analog simulation,calibration method,measurement accuracy,nanoprobe design,and wearable improvement.Furthermore,we discuss the biomedical applications of PA temperature monitoring technology in photothermal therapy and ultrasound therapy,finally,anticipating future developments in the field.展开更多
Photoacoustic imaging(PAI)employs short laser pulses to excite absorbing materials,producing ultrasonic waves spanning a broad spectrum of frequencies.These ultrasonic waves are captured surrounding the sample and uti...Photoacoustic imaging(PAI)employs short laser pulses to excite absorbing materials,producing ultrasonic waves spanning a broad spectrum of frequencies.These ultrasonic waves are captured surrounding the sample and utilized to reconstruct the initial pressure distribution tomographically.Despite the wide spectral range of the laser-generated photoacoustic signal,an individual transducer can only capture a limited segment of the signal due to its constrained bandwidth.Herein,we have developed a multi-bandwidth ring array photoacoustic computed tomography(PACT)system,incorporating a probe with two semi-ring arrays:one for high frequency and the other for low frequency.Utilizing the two semi-ring array PAIs,we have devised a specialized deep learning model,comprising two serially connected U-net architectures,to autonomously generate multi-bandwidth full-view PAIs.Preliminary results from simulations and in vivo experiments illustrate the system's robust multi-bandwidth imaging capabilities,achieving an excellent PSNR of 34.78 dB and a structural similarity index measure(SSIM)of 0.94 in the high-frequency reconstruction of complex mouse abdominal structures.This innovative PACT system is notable for its capability to seamlessly acquire multi-bandwidth full-view PAIs,thereby advancing the application of PAI technology in the biomedical domain.展开更多
Foundation models(FMs)have rapidly evolved and have achieved signicant accomplishments in computer vision tasks.Specically,the prompt mechanism conveniently allows users to integrate image prior information into the m...Foundation models(FMs)have rapidly evolved and have achieved signicant accomplishments in computer vision tasks.Specically,the prompt mechanism conveniently allows users to integrate image prior information into the model,making it possible to apply models without any training.Therefore,we proposed a workflow based on foundation models and zero training to solve the tasks of photoacoustic(PA)image processing.We employed the Segment Anything Model(SAM)by setting simple prompts and integrating the model's outputs with prior knowledge of the imaged objects to accomplish various tasks,including:(1)removing the skin signal in three-dimensional PA image rendering;(2)dual speed-of-sound reconstruction,and(3)segmentation ofnger blood vessels.Through these demonstrations,we have concluded that FMs can be directly applied in PA imaging without the requirement for network design and training.This potentially allows for a hands-on,convenient approach to achieving efficient and accurate segmentation of PA images.This paper serves as a comprehensive tutorial,facilitating the mastery of the technique through the provision of code and sample datasets.展开更多
Acoustic-resolution photoacoustic microscopy(AR-PAM)suffers from degraded lateral resolution due to acoustic diffraction.Here,a resolution enhancement strategy for AR-PAM via a mean-reverting diffusion model was propo...Acoustic-resolution photoacoustic microscopy(AR-PAM)suffers from degraded lateral resolution due to acoustic diffraction.Here,a resolution enhancement strategy for AR-PAM via a mean-reverting diffusion model was proposed to achieve the transition from acoustic resolution to optical resolution.By modeling the degradation process from high-resolution image to low-resolution AR-PAM image with stable Gaussian noise(i.e.,mean state),a mean-reverting diffusion model is trained to learn prior information of the data distribution.Then the learned prior is employed to generate a high-resolution image from the AR-PAM image by iteratively sampling the noisy state.The performance of the proposed method was validated utilizing the simulated and in vivo experimental data under varying lateral resolutions and noise levels.The results show that an over 3.6-fold enhancement in lateral resolution was achieved.The image quality can be effectively improved,with a notable enhancement of∼66%in PSNR and∼480%in SSIM for in vivo data.展开更多
Deep learning(DL)is making significant inroads into biomedical imaging as it provides novel and powerful ways of accurately and efficiently improving the image quality of photoacoustic microscopy(PAM).Off-the-shelf DL...Deep learning(DL)is making significant inroads into biomedical imaging as it provides novel and powerful ways of accurately and efficiently improving the image quality of photoacoustic microscopy(PAM).Off-the-shelf DL models,however,do not necessarily obey the fundamental governing laws of PAM physical systems,nor do they generalize well to scenarios on which they have not been trained.In this work,a physics-embedded degeneration learning(PEDL)approach is proposed to enhance the image quality of PAM with a self-attention enhanced U-Net network,which obtains greater physical consistency,improves data efficiency,and higher adaptability.The proposed method is demonstrated on both synthetic and real datasets,including animal experiments in vivo(blood vessels of mouse's ear and brain).And the results show that compared with previous DL methods,the PEDL algorithm exhibits good performance in recovering PAM images qualitatively and quantitatively.It overcomes the challenges related to training data,accuracy,and robustness which a typical data-driven approach encounters,whose exemplary application envisions to provide a new perspective for existing DL tools of enhanced PAM.展开更多
The brain lymphatic system plays a crucial role in maintaining homeostasis,clearing metabolic waste,and regulating neuroinflammation.Its dysfunction is strongly linked to neurodegenerative diseases such as Alzheimer&#...The brain lymphatic system plays a crucial role in maintaining homeostasis,clearing metabolic waste,and regulating neuroinflammation.Its dysfunction is strongly linked to neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease.In this study,we employed dual-contrast functionalphotoacoustic microscopy to evaluate the impact of lipopolysaccharide-induced central nervous system inflammation on brain lymphatic function and to explore the protective effects of the P2X7 receptor(P2X7R)antagonist.Our findings demonstrated that lipopolysac-charide intervention led to impaired function of the meningeal lymphatic vessels,which was par-tially restored by the P2X7R antagonist,whereas its effects on the glymphatic system and cerebral vessels were minimal.This study further supports the feasibility of photoacoustic microscopy for assessing brain lymphatic function and highlights the therapeutic potential of P2X7R antagonism.These findings suggest that P2X7R may serve as a key target for modulating brain-lymphatic interactions,providing an experimental foundation for developing intervention strategies for neuroinflammatory and neurodegenerative diseases.展开更多
Optical-resolution photoacoustic microscopy is a novel imaging technique that combines the advantages of optical and ultrasound imaging,enabling high-resolution visualization of biological tissues at the micrometer sc...Optical-resolution photoacoustic microscopy is a novel imaging technique that combines the advantages of optical and ultrasound imaging,enabling high-resolution visualization of biological tissues at the micrometer scale.However,the divergence of the excited Gaussian beam limits the depth-of-field of the system to less than 100μm,which hinders accurate three-dimensional imaging of living tissues and restrictsits applicability in biological research.Therefore,there is an urgent need for an effective method to enhance the depth-of-field without altering the hardware configuration.This paper presents a photoacoustic microscopy depth-of-field extension method and system based on three-dimensional continuity and sparsity deconvolution.This method utilizes a depth-varying point spread function and incorporates continuity and sparsity con-straints into the deconvolution process to mitigate the effect of background noise,enhancing the stability and accuracy of the depth-of-field extension.Experimental results using tungsten wire phantoms suggest that the depth-of-field of system can be extended to 650 pm,which is 7.2 times greater than conventional system,while improving the resolution of the defocused region by an average factor of 3.5.Furthermore,experiments on zebrafish and nude mouse ears with irregular topologies demonstrate that the proposed method successfully overcomes image blurring and the loss of structural information due to limited depth-of-field.All the results suggest that the system with higher lateral resolution and enhanced depth-of-field has significant potential for a wide range of practical biomedical applications.展开更多
Photoacoustic imag ing(PAI)is a nonin vasive biomedical imag ing tech no logy capable of multiscale imag ing of biological samples from orga ns dow n to cells.Multiscale PAI requires differe nt ultraso und tra nsducer...Photoacoustic imag ing(PAI)is a nonin vasive biomedical imag ing tech no logy capable of multiscale imag ing of biological samples from orga ns dow n to cells.Multiscale PAI requires differe nt ultraso und tra nsducers that are flat or focused because the current widely-used piezoelectric transducers are rigid and lack the flexibility to tune their spatial ultrasound responses.Inspired by the rapidly-developing flexible photonics,we exploited the inherent flexibility and low-loss features of optical fibers to develop a flexible fiber-laser ultrasound sensor(FUS)for multiscale PAI.By simply bending the fiber laser from straight to curved geometry,the spatial ultraso und resp onse of the FUS can be tuned for both wide-view optical-resolution photoacoustic microscopy at optical diffraction-limited depth(~1 mm)and photoacoustic computed tomography at optical dissipation-limited depth of several centimeters.A radio-frequency demodulation was employed to get the readout of the beat frequency variation of two orthogonal polarization modes in the FUS output,which ensures low-noise and stable ultrasound detection.Compared to traditional piezoelectrical transducers with fixed ultrasound responses once manufactured,the flexible FUS provides the freedom to design multiscale PAI modalities including wearable microscope,intravascular endoscopy,and portable tomography system,which is attractive to fundamental biologic-al/medical studies and clinical applications.展开更多
Photoacoustic(PA)imaging has been widely used in biomedical research and preclinical studies during the past two decades.It has also been explored for nondestructive testing and evaluation(NDT/E)and for industrial app...Photoacoustic(PA)imaging has been widely used in biomedical research and preclinical studies during the past two decades.It has also been explored for nondestructive testing and evaluation(NDT/E)and for industrial applications.This paper describes the basic principles of PA technology for NDT/E and its applications in recent years.PA technology for NDT/E includes the use of a modulated continuous-wave laser and a pulsed laser for PA wave excitation,PA-generated ultrasonic waves,and all-optical PA wave excitation and detection.PA technology for NDT/E has demonstrated broad applications,including the imaging of railway cracks and defects,the imaging of Li metal batteries,the measurements of the porosity and Young’s modulus,the detection of defects and damage in silicon wafers,and a visualization of underdrawings in paintings.展开更多
Photoacoustic imaging,an emerging biomedical imaging modality,holds great promise for preclinical and clinical researches.It combines the high optical contrast and high ultrasound resolution by converting laser excita...Photoacoustic imaging,an emerging biomedical imaging modality,holds great promise for preclinical and clinical researches.It combines the high optical contrast and high ultrasound resolution by converting laser excitation into ultrasonic emission.In order to generate photoacoustic signal e±-ciently,bulky Q-switched solid-state laser systems are most commonly used as excitation sources and hence limit its commercialization.As an alternative,the miniaturized semiconductor laser system has the advantages of being inexpensive,compact,and robust,which makes a signi¯cant e®ect on production-forming design.It is also desirable to obtain a wavelength in a wide range from visible to nearinfrared spectrum for multispectral applications.Focussing on practical aspect,this paper reviews the state-of-the-art developments of low-cost photoacoustic system with laser diode and light-emitting diode excitation source and highlights a few representative installations in the past decade.展开更多
Photoacoustic imaging acquires the absorption contrast of biological tissue with ultrasound resolution. It has been broadly investigated in biomedicine for animal and clinical studies. Recently, a micro-electromechani...Photoacoustic imaging acquires the absorption contrast of biological tissue with ultrasound resolution. It has been broadly investigated in biomedicine for animal and clinical studies. Recently, a micro-electromechanical system(MEMS) scanner has been utilized in photoacoustic imaging systems to enhance their performance and extend the realm of applications. The review provides a recap of recent developments in photoacoustic imaging using MEMS scanner, from instrumentation to applications. The topics include the design of MEMS scanner, its use in photoacoustic microscopy, miniature imaging probes, development of dual-modality systems,as well as cutting-edge bio-imaging studies.展开更多
Photoacoustic imaging(PAI)is a new biomedical imaging technology that provides a mixed contrast mechanism and excellent spatial resolution in biological tissues.It is a non-invasive technology that can provide in vivo...Photoacoustic imaging(PAI)is a new biomedical imaging technology that provides a mixed contrast mechanism and excellent spatial resolution in biological tissues.It is a non-invasive technology that can provide in vivo anatomical and functional information.This technology has great application potential in microscopic imaging and endoscope system.In recent years,the devel-opment of micro electro mechanical system(MEMS)technology has promoted the improvement and miniaturization of the photoacoustic imaging system,as well as its preclinical and clinical appli-cations.This paper introduces the research progress of MEMS technology in photoacoustic micro-scope systems and the miniaturization of photoacoustic endoscope ultrasonic transducers,and points out the shortcomings of existing technology and the direction of future development.展开更多
Photoacoustic imaging(PAI)is often performed simultaneously with ultrasound imaging and can provide functional and cellular information regarding the tissues in the anatomical markers of the imaging.This paper describ...Photoacoustic imaging(PAI)is often performed simultaneously with ultrasound imaging and can provide functional and cellular information regarding the tissues in the anatomical markers of the imaging.This paper describes in detail the basic principles of photoacoustic/ultrasound(PA/US)imaging and its application in recent years.It includes near-infrared-region PA,photothermal,photodynamic,and multimode imaging techniques.Particular attention is given to the relationship between PAI and ultrasonic imaging;the latest high-frequency PA/US imaging of small animals,which involves not only B-mode,but also color Doppler mode,power Doppler mode,and nonlinear imaging mode;the ultrasonic model combined with PAI,including the formation of multimodal imaging;the preclinical imaging methods;and the most effective detection methods for clinical research for the future.展开更多
Photoacoustic therapy,using the photoacoustic efect of agents for selectively kling tumor cells,has shown pronising for treat ing tumor.Utilization of high optical absorption probes can help to effectively improve the...Photoacoustic therapy,using the photoacoustic efect of agents for selectively kling tumor cells,has shown pronising for treat ing tumor.Utilization of high optical absorption probes can help to effectively improve the photoacoustic ther apy efficiency.Herein,we report a novel high-absorpt:ion photoacoustic probe that is composed of indocyanine green(ICG)and gr aphene oxide(GO),entitled GO-ICG,for photoacoustic ther apy.The attached ICG with narrow absorption spectral profile has strong optical absorption in the infrared region.The absorption spectrum of the GO-ICG solution reveals that the GO-ICG particles exhibited a 10-fold higher absorbance at 780 nm(its peak absorbance)as compared with GO.Importantly,ICG's fluorescence is quenched by GO via fuorescence resonance energy transfer.As a result,GO-ICG can high efficiently convert the absorbed light energy to acoustic wave under pulsed laser irradiation.We further demonstrate that GO-ICG can produce stronger photoacoustic wave than the GO and ICG alone.Moreover,we conjugate this contrast agent with integrin 0。As mono dlonal antibody to molecularly target the U87-MG human glioblastoma cells for selective tumor cell killing.Finally,our results testify that the photoacoustic therapy eficiency of GO-ICG is higher than the existing photoacoustic therapy agent.Our work demonstrates that GO-ICG is a high efficiency photo-acoustic therapy agent.This novel photoacoustic probe is likely to be an available candidate for tumor therapy.展开更多
Photoacoustic mesoscopy(PAMe) offers high-sensitivity in vivo imaging based on the rich optical contrast in biological tissues,with sub-100-micron resolutions at a few millimeters depth. By benefiting from low ultraso...Photoacoustic mesoscopy(PAMe) offers high-sensitivity in vivo imaging based on the rich optical contrast in biological tissues,with sub-100-micron resolutions at a few millimeters depth. By benefiting from low ultrasonic scattering,this emerging technology has pushed the penetration depth beyond the optical diffuse limit unprecedented for high-resolution optical methods.Here,we review ed the state-of-art implementations of PAMe and their achievements in biological and primary clinical applications. With the high-frequency focused ultrasonic detector,the high-resolution optical visualization can be achieved by utilizing various PAMe systems. These capabilities of PAMe have made it well applicable for understanding the biological mechanisms,exploring the pathological features and analyzing the characteristics of human skin. Future improvements and prospects of PAMe are also mentioned,suggesting its great potential tow ards the corresponding emerging biomedical and clinical applications.展开更多
Photoacoustic(PA)microscopy is being increasingly used to visualize the microcirculation of the brain cortex at the micron level in living rodents.By combining it with long-term cranial window techniques,vasculature c...Photoacoustic(PA)microscopy is being increasingly used to visualize the microcirculation of the brain cortex at the micron level in living rodents.By combining it with long-term cranial window techniques,vasculature can be monitored over a period of days extending to months through a field of view.To fulfill the requirements of long-term in vivo PA imaging,the cranial window must involve a simple and rapid surgical procedure,biological compatibility,and sufficient optical-acoustic transparency,which are major challenges.Recently,several cranial window techniques have been reported for longitudinal PA imaging.Here,the development of chronic cranial windows for PA imaging is reviewed and its technical details are discussed,including window installation,imaging quality,and longitudinal stability.展开更多
Miniaturized sound generators are attractive to realize intriguing functions.Thermoacoustic device’s application is seriously limited due to the frequency-doubling phenomenon.To address this issue,photoacoustic sound...Miniaturized sound generators are attractive to realize intriguing functions.Thermoacoustic device’s application is seriously limited due to the frequency-doubling phenomenon.To address this issue,photoacoustic sound generator is considered as a promising alternative.Here,based on vertical single-wall carbon nanotubes(CNTs)array,we introduce a photoacoustic sound generator with internal nano-Helmholtz cavity.Different from traditional device that generates sound by periodically heating up the open space air around material,this sound generator produces an audio signal by forming a forced vibration of the air inside the CNTs.Interestingly,anomalous photoacoustic behavior is observed that the sound pressure level(SPL)curve has a resonance peak,the corresponding frequency of which is inversely proportional to the CNTs array’s height.Furthermore,the energy conversion efficiency of this photoacoustic device is 1.64 times as large as that of a graphene sponge-based photoacoustic device.Most importantly,this device can be employed for music playing,bringing a new clew for the development of musical instruments in the future.展开更多
基金supported by the National Key R&D Program of China,No.2023YFC2509700the Beijing Natural Science Foundation-Haidian Original Innovation Joint Fund,No.L232141the Research and Application of Clinical Characteristic Diagnosis and Treatment Program,No.Z221100007422019(all to WD)。
文摘Spinal cord injury is a severe neurological disorder;however,current treatment methods often fail to restore nerve function effectively.Spinal cord stimulation via electrical signals is a promising therapeutic modality for spinal cord injury.Based on similar principles,this review aims to explore the potential of optical and acoustic neuromodulation techniques,emphasizing their benefits in the context of spinal cord injury.Photoacoustic imaging,renowned for its noninvasive nature,high-resolution capabilities,and cost-effectiveness,is well recognized for its role in early diagnosis,dynamic monitoring,and surgical guidance in stem cell therapies for spinal cord injury.Moreover,photoacoustodynamic therapy offers multiple pathways for tissue regeneration.Optogenetics and sonogenetics use genetic engineering to achieve precise neuronal activation,while photoacoustoelectric therapy leverages photovoltaic materials for electrical modulation of the nervous system,introducing an innovative paradigm for nerve system disorder management.Collectively,these advancements represent a transformative shift in the diagnosis and treatment of spinal cord injury,with the potential to significantly enhance nerve function remodeling and improve patient outcomes.
基金supported by University of Macao,China,Nos.MYRG2022-00054-FHS and MYRG-GRG2023-00038-FHS-UMDF(to ZY)the Macao Science and Technology Development Fund,China,Nos.FDCT0048/2021/AGJ and FDCT0020/2019/AMJ and FDCT 0011/2018/A1(to ZY)Natural Science Foundation of Guangdong Province of China,No.EF017/FHS-YZ/2021/GDSTC(to ZY)。
文摘To investigate the mechanisms underlying the onset and progression of ischemic stroke,some methods have been proposed that can simultaneously monitor and create embolisms in the animal cerebral cortex.However,these methods often require complex systems and the effect of age on cerebral embolism has not been adequately studied,although ischemic stroke is strongly age-related.In this study,we propose an optical-resolution photoacoustic microscopy-based visualized photothrombosis methodology to create and monitor ischemic stroke in mice simultaneously using a 532 nm pulsed laser.We observed the molding process in mice of different ages and presented age-dependent vascular embolism differentiation.Moreover,we integrated optical coherence tomography angiography to investigate age-associated trends in cerebrovascular variability following a stroke.Our imaging data and quantitative analyses underscore the differential cerebrovascular responses to stroke in mice of different ages,thereby highlighting the technique's potential for evaluating cerebrovascular health and unraveling age-related mechanisms involved in ischemic strokes.
基金Project supported by the National Natural Science Foundation of China(Grant No.42105176)the National University of Defense Technology Independent Research Project(Grant No.ZK21-40)。
文摘We theoretically investigate the feasibility of reconstructing the transverse structures of femtosecond laser filaments in air by photoacoustic tomography.To simulate the emission and transmission of filament-induced ultrasonic signals more truly,a series of experimentally recorded cross-sectional images are used to simulate the initial pressure rise from multiple filaments(MFs).The aperture size and sensitivity of the detector was incorporated into the reconstruction algorithm.The results show that frequency of acoustic signals induced by MFs with maximum volumetric energy density~100 k J/m^(3)is about 2 MHz below.The initial spatial distribution of optical filaments can be clearly reconstructed with the back projection based algorithm.We recommend a PAT system with transducers of a lower central frequency and a stronger apodization working at a longer scanning radius can be used in photoacoustic image reconstruction of femtosecond laser multifilaments.This study demonstrates the feasibility of using photoacoustic tomography to reconstruct femtosecond multifilament images,which is helpful for studying the complex dynamic processes of multifilament and multifilament manipulation and is also valuable for the remote applications of laser filaments.
基金supported by the National Natural Science Foundation of China(No.12174125)Guangdong Basic and Applied Basic Research Foundation(Nos.2024A1515010522 and 2021A1515011874).
文摘The temperature of an organism provides key insights into its physiological and pathological status.Temperature monitoring can effectively assess potential health issues and plays a critical role in thermal treatment.Photoacoustic imaging(PAI)has enabled multi-scale imaging,from cells to tissues and organs,where its high contrast,deep penetration,and high resolution make it an emerging tool in biomedical imaging field.Benefiting from the linear correlation between the Grüneisen parameter and temperature within the range of 10–55∘C,the PAI has been developed as novel noninvasive label-free tool for temperature monitoring especially for thermotherapy mediated by laser,ultrasound,and microwave.Additionally,by utilizing temperature-responsive photoacoustic nanoprobes,the temperature information of the targeted organism can also be extracted with enhanced imaging contrast and specificity.This review elucidates the basic principles of temperature monitoring technology implemented by PAI,further highlighting the limitations of traditional photoacoustic thermometry,and summarizes recent technological advancements in analog simulation,calibration method,measurement accuracy,nanoprobe design,and wearable improvement.Furthermore,we discuss the biomedical applications of PA temperature monitoring technology in photothermal therapy and ultrasound therapy,finally,anticipating future developments in the field.
基金supported by the National Key R&D Program of China[Grant No.2023YFF0713600]the National Natural Science Foundation of China[Grant No.62275062]+2 种基金the Project of Shandong Innovation and Startup Community of High-end Medical Apparatus and Instruments[Grant No.2021-SGTTXM-005]the Shandong Province Technology Innovation Guidance Plan(Central Leading Local Science and Technology Development Fund)[Grant No.YDZX2023115]the Taishan Scholar Special Funding Project of Shandong Province,and the Shandong Laboratory of Advanced Biomaterials and Medical Devices in Weihai[Grant No.ZL202402].
文摘Photoacoustic imaging(PAI)employs short laser pulses to excite absorbing materials,producing ultrasonic waves spanning a broad spectrum of frequencies.These ultrasonic waves are captured surrounding the sample and utilized to reconstruct the initial pressure distribution tomographically.Despite the wide spectral range of the laser-generated photoacoustic signal,an individual transducer can only capture a limited segment of the signal due to its constrained bandwidth.Herein,we have developed a multi-bandwidth ring array photoacoustic computed tomography(PACT)system,incorporating a probe with two semi-ring arrays:one for high frequency and the other for low frequency.Utilizing the two semi-ring array PAIs,we have devised a specialized deep learning model,comprising two serially connected U-net architectures,to autonomously generate multi-bandwidth full-view PAIs.Preliminary results from simulations and in vivo experiments illustrate the system's robust multi-bandwidth imaging capabilities,achieving an excellent PSNR of 34.78 dB and a structural similarity index measure(SSIM)of 0.94 in the high-frequency reconstruction of complex mouse abdominal structures.This innovative PACT system is notable for its capability to seamlessly acquire multi-bandwidth full-view PAIs,thereby advancing the application of PAI technology in the biomedical domain.
基金support from Strategic Project of Precision Surgery,Tsinghua UniversityInitiative Scientific Research Program,Institute for Intelligent Healthcare,Tsinghua University+5 种基金Tsinghua-Foshan Institute of Advanced ManufacturingNational Natural Science Foundation of China(61735016)Beijing Nova Program(20230484308)Young Elite Scientists Sponsorship Program by CAST(2023QNRC001)Youth Elite Program of Beijing Friendship Hospital(YYQCJH2022-9)Science and Technology Program of Beijing Tongzhou District(KJ2023CX012).
文摘Foundation models(FMs)have rapidly evolved and have achieved signicant accomplishments in computer vision tasks.Specically,the prompt mechanism conveniently allows users to integrate image prior information into the model,making it possible to apply models without any training.Therefore,we proposed a workflow based on foundation models and zero training to solve the tasks of photoacoustic(PA)image processing.We employed the Segment Anything Model(SAM)by setting simple prompts and integrating the model's outputs with prior knowledge of the imaged objects to accomplish various tasks,including:(1)removing the skin signal in three-dimensional PA image rendering;(2)dual speed-of-sound reconstruction,and(3)segmentation ofnger blood vessels.Through these demonstrations,we have concluded that FMs can be directly applied in PA imaging without the requirement for network design and training.This potentially allows for a hands-on,convenient approach to achieving efficient and accurate segmentation of PA images.This paper serves as a comprehensive tutorial,facilitating the mastery of the technique through the provision of code and sample datasets.
基金pported by the National Natural Science Foundation of China(62265011 and 62122033)Jiangxi Provincial Natural Science Foundation(20224BAB212006 and 20232BAB 202038)National Key Research and Develop-ment Program of China(2023YFF1204302)。
文摘Acoustic-resolution photoacoustic microscopy(AR-PAM)suffers from degraded lateral resolution due to acoustic diffraction.Here,a resolution enhancement strategy for AR-PAM via a mean-reverting diffusion model was proposed to achieve the transition from acoustic resolution to optical resolution.By modeling the degradation process from high-resolution image to low-resolution AR-PAM image with stable Gaussian noise(i.e.,mean state),a mean-reverting diffusion model is trained to learn prior information of the data distribution.Then the learned prior is employed to generate a high-resolution image from the AR-PAM image by iteratively sampling the noisy state.The performance of the proposed method was validated utilizing the simulated and in vivo experimental data under varying lateral resolutions and noise levels.The results show that an over 3.6-fold enhancement in lateral resolution was achieved.The image quality can be effectively improved,with a notable enhancement of∼66%in PSNR and∼480%in SSIM for in vivo data.
基金supported by National Natural Science Foundation of China(62227818,12204239,62275121)Youth Foundation of Jiangsu Province(BK20220946)+1 种基金Fundamental Research Funds for the Central Universities(30923011024)Open Research Fund of Jiangsu Key Laboratory of Spectral Imaging&Intelligent Sense(JSGP202201).
文摘Deep learning(DL)is making significant inroads into biomedical imaging as it provides novel and powerful ways of accurately and efficiently improving the image quality of photoacoustic microscopy(PAM).Off-the-shelf DL models,however,do not necessarily obey the fundamental governing laws of PAM physical systems,nor do they generalize well to scenarios on which they have not been trained.In this work,a physics-embedded degeneration learning(PEDL)approach is proposed to enhance the image quality of PAM with a self-attention enhanced U-Net network,which obtains greater physical consistency,improves data efficiency,and higher adaptability.The proposed method is demonstrated on both synthetic and real datasets,including animal experiments in vivo(blood vessels of mouse's ear and brain).And the results show that compared with previous DL methods,the PEDL algorithm exhibits good performance in recovering PAM images qualitatively and quantitatively.It overcomes the challenges related to training data,accuracy,and robustness which a typical data-driven approach encounters,whose exemplary application envisions to provide a new perspective for existing DL tools of enhanced PAM.
基金supported by STI2030-Major Projects(No.2022ZD0212200)National Natural Science Foundation of China(No.62305118)+1 种基金Guangdong Basic and Applied Basic Research Foundation(No.2025A1515010953)China Postdoctoral Science Foundation(No.2022M721223).
文摘The brain lymphatic system plays a crucial role in maintaining homeostasis,clearing metabolic waste,and regulating neuroinflammation.Its dysfunction is strongly linked to neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease.In this study,we employed dual-contrast functionalphotoacoustic microscopy to evaluate the impact of lipopolysaccharide-induced central nervous system inflammation on brain lymphatic function and to explore the protective effects of the P2X7 receptor(P2X7R)antagonist.Our findings demonstrated that lipopolysac-charide intervention led to impaired function of the meningeal lymphatic vessels,which was par-tially restored by the P2X7R antagonist,whereas its effects on the glymphatic system and cerebral vessels were minimal.This study further supports the feasibility of photoacoustic microscopy for assessing brain lymphatic function and highlights the therapeutic potential of P2X7R antagonism.These findings suggest that P2X7R may serve as a key target for modulating brain-lymphatic interactions,providing an experimental foundation for developing intervention strategies for neuroinflammatory and neurodegenerative diseases.
基金supported by the National Key R&D Program of China[Grant No.2022YFC2402400]the National Natural Science Foundation of China[Grant No.62275062]+2 种基金Project of Shandong Innovation and Startup Community of High-end Medical Apparatus and Instruments[Grant Nos.2023-SGTTXM-002 and 2024-SGTTXM-005]the Shandong Province Technology Innovation Guidance Plan(Central Leading Local Science and Technology Development Fund)[Grant No.YDZX2023115]the Taishan Scholar Special Funding Project of Shandong Province,and the Shandong Laboratory of Advanced Biomaterials and Medical Devices in Weihai[Grant No.ZL202402].
文摘Optical-resolution photoacoustic microscopy is a novel imaging technique that combines the advantages of optical and ultrasound imaging,enabling high-resolution visualization of biological tissues at the micrometer scale.However,the divergence of the excited Gaussian beam limits the depth-of-field of the system to less than 100μm,which hinders accurate three-dimensional imaging of living tissues and restrictsits applicability in biological research.Therefore,there is an urgent need for an effective method to enhance the depth-of-field without altering the hardware configuration.This paper presents a photoacoustic microscopy depth-of-field extension method and system based on three-dimensional continuity and sparsity deconvolution.This method utilizes a depth-varying point spread function and incorporates continuity and sparsity con-straints into the deconvolution process to mitigate the effect of background noise,enhancing the stability and accuracy of the depth-of-field extension.Experimental results using tungsten wire phantoms suggest that the depth-of-field of system can be extended to 650 pm,which is 7.2 times greater than conventional system,while improving the resolution of the defocused region by an average factor of 3.5.Furthermore,experiments on zebrafish and nude mouse ears with irregular topologies demonstrate that the proposed method successfully overcomes image blurring and the loss of structural information due to limited depth-of-field.All the results suggest that the system with higher lateral resolution and enhanced depth-of-field has significant potential for a wide range of practical biomedical applications.
基金This work was supported by the National Natural Science Foundation of China(61775083,61705082,61805102,and 61860206002)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2019BT02X105)Guangzhou Science and Technology Plan(201904020032).
文摘Photoacoustic imag ing(PAI)is a nonin vasive biomedical imag ing tech no logy capable of multiscale imag ing of biological samples from orga ns dow n to cells.Multiscale PAI requires differe nt ultraso und tra nsducers that are flat or focused because the current widely-used piezoelectric transducers are rigid and lack the flexibility to tune their spatial ultrasound responses.Inspired by the rapidly-developing flexible photonics,we exploited the inherent flexibility and low-loss features of optical fibers to develop a flexible fiber-laser ultrasound sensor(FUS)for multiscale PAI.By simply bending the fiber laser from straight to curved geometry,the spatial ultraso und resp onse of the FUS can be tuned for both wide-view optical-resolution photoacoustic microscopy at optical diffraction-limited depth(~1 mm)and photoacoustic computed tomography at optical dissipation-limited depth of several centimeters.A radio-frequency demodulation was employed to get the readout of the beat frequency variation of two orthogonal polarization modes in the FUS output,which ensures low-noise and stable ultrasound detection.Compared to traditional piezoelectrical transducers with fixed ultrasound responses once manufactured,the flexible FUS provides the freedom to design multiscale PAI modalities including wearable microscope,intravascular endoscopy,and portable tomography system,which is attractive to fundamental biologic-al/medical studies and clinical applications.
基金S.-L.Chen acknowledges funding from the National Natural Science Foundation of China,No.61775134C.Tian acknowledges funding from the National Natural Science Foundation of China,No.61705216the Anhui Science and Technology Department,No.18030801138.
文摘Photoacoustic(PA)imaging has been widely used in biomedical research and preclinical studies during the past two decades.It has also been explored for nondestructive testing and evaluation(NDT/E)and for industrial applications.This paper describes the basic principles of PA technology for NDT/E and its applications in recent years.PA technology for NDT/E includes the use of a modulated continuous-wave laser and a pulsed laser for PA wave excitation,PA-generated ultrasonic waves,and all-optical PA wave excitation and detection.PA technology for NDT/E has demonstrated broad applications,including the imaging of railway cracks and defects,the imaging of Li metal batteries,the measurements of the porosity and Young’s modulus,the detection of defects and damage in silicon wafers,and a visualization of underdrawings in paintings.
基金the National Natural Scienti¯c Foundation of China(11664011,11304129)the Science and Technology Program of Jiangxi,China(20151BAB217025,20132BBG70033,GJJ150790)the Intramural Top-notch Youth Talent Program of JXSTNU,China(2013QNBJRC003).
文摘Photoacoustic imaging,an emerging biomedical imaging modality,holds great promise for preclinical and clinical researches.It combines the high optical contrast and high ultrasound resolution by converting laser excitation into ultrasonic emission.In order to generate photoacoustic signal e±-ciently,bulky Q-switched solid-state laser systems are most commonly used as excitation sources and hence limit its commercialization.As an alternative,the miniaturized semiconductor laser system has the advantages of being inexpensive,compact,and robust,which makes a signi¯cant e®ect on production-forming design.It is also desirable to obtain a wavelength in a wide range from visible to nearinfrared spectrum for multispectral applications.Focussing on practical aspect,this paper reviews the state-of-the-art developments of low-cost photoacoustic system with laser diode and light-emitting diode excitation source and highlights a few representative installations in the past decade.
基金the National Natural Science Foundation of China(No.61405112)the National High Technology Research and Development Program(863)of China(No.2015AA020944)
文摘Photoacoustic imaging acquires the absorption contrast of biological tissue with ultrasound resolution. It has been broadly investigated in biomedicine for animal and clinical studies. Recently, a micro-electromechanical system(MEMS) scanner has been utilized in photoacoustic imaging systems to enhance their performance and extend the realm of applications. The review provides a recap of recent developments in photoacoustic imaging using MEMS scanner, from instrumentation to applications. The topics include the design of MEMS scanner, its use in photoacoustic microscopy, miniature imaging probes, development of dual-modality systems,as well as cutting-edge bio-imaging studies.
基金supported by the National Natural Science Foundation of China(No.32101153)the Fundamental Research Funds for the Central Universities(No.2021CX11018).
文摘Photoacoustic imaging(PAI)is a new biomedical imaging technology that provides a mixed contrast mechanism and excellent spatial resolution in biological tissues.It is a non-invasive technology that can provide in vivo anatomical and functional information.This technology has great application potential in microscopic imaging and endoscope system.In recent years,the devel-opment of micro electro mechanical system(MEMS)technology has promoted the improvement and miniaturization of the photoacoustic imaging system,as well as its preclinical and clinical appli-cations.This paper introduces the research progress of MEMS technology in photoacoustic micro-scope systems and the miniaturization of photoacoustic endoscope ultrasonic transducers,and points out the shortcomings of existing technology and the direction of future development.
文摘Photoacoustic imaging(PAI)is often performed simultaneously with ultrasound imaging and can provide functional and cellular information regarding the tissues in the anatomical markers of the imaging.This paper describes in detail the basic principles of photoacoustic/ultrasound(PA/US)imaging and its application in recent years.It includes near-infrared-region PA,photothermal,photodynamic,and multimode imaging techniques.Particular attention is given to the relationship between PAI and ultrasonic imaging;the latest high-frequency PA/US imaging of small animals,which involves not only B-mode,but also color Doppler mode,power Doppler mode,and nonlinear imaging mode;the ultrasonic model combined with PAI,including the formation of multimodal imaging;the preclinical imaging methods;and the most effective detection methods for clinical research for the future.
基金supported by the National Basic Research Program of China(2011CB9104022010CB732602)+3 种基金the National Natural Science Foundation of China(613611604146133100181127004)the Guangdong Natural Science Foundation(S2013020012646).
文摘Photoacoustic therapy,using the photoacoustic efect of agents for selectively kling tumor cells,has shown pronising for treat ing tumor.Utilization of high optical absorption probes can help to effectively improve the photoacoustic ther apy efficiency.Herein,we report a novel high-absorpt:ion photoacoustic probe that is composed of indocyanine green(ICG)and gr aphene oxide(GO),entitled GO-ICG,for photoacoustic ther apy.The attached ICG with narrow absorption spectral profile has strong optical absorption in the infrared region.The absorption spectrum of the GO-ICG solution reveals that the GO-ICG particles exhibited a 10-fold higher absorbance at 780 nm(its peak absorbance)as compared with GO.Importantly,ICG's fluorescence is quenched by GO via fuorescence resonance energy transfer.As a result,GO-ICG can high efficiently convert the absorbed light energy to acoustic wave under pulsed laser irradiation.We further demonstrate that GO-ICG can produce stronger photoacoustic wave than the GO and ICG alone.Moreover,we conjugate this contrast agent with integrin 0。As mono dlonal antibody to molecularly target the U87-MG human glioblastoma cells for selective tumor cell killing.Finally,our results testify that the photoacoustic therapy eficiency of GO-ICG is higher than the existing photoacoustic therapy agent.Our work demonstrates that GO-ICG is a high efficiency photo-acoustic therapy agent.This novel photoacoustic probe is likely to be an available candidate for tumor therapy.
基金the National Natural Science Foundation of China (Grant Nos.81401453,81371602,61475115,61475116,61575140,81571723,and 81671728)the Tianjin Municipal Government of China (Grant Nos.14JCQNJC14400,15JCZDJC31800,15JCQNJC14500,and 16JCZDJC31200)
文摘Photoacoustic mesoscopy(PAMe) offers high-sensitivity in vivo imaging based on the rich optical contrast in biological tissues,with sub-100-micron resolutions at a few millimeters depth. By benefiting from low ultrasonic scattering,this emerging technology has pushed the penetration depth beyond the optical diffuse limit unprecedented for high-resolution optical methods.Here,we review ed the state-of-art implementations of PAMe and their achievements in biological and primary clinical applications. With the high-frequency focused ultrasonic detector,the high-resolution optical visualization can be achieved by utilizing various PAMe systems. These capabilities of PAMe have made it well applicable for understanding the biological mechanisms,exploring the pathological features and analyzing the characteristics of human skin. Future improvements and prospects of PAMe are also mentioned,suggesting its great potential tow ards the corresponding emerging biomedical and clinical applications.
基金This study was supported by the National Natural Science Foundation of China,Nos.62022037,61775028,81571722,61528401Department of Science and Technology of Guangdong Province,Nos.2019ZT08Y191,SZBL2020090501013+1 种基金Shenzhen Science and Technology ProgramNos.KQTD20190929172743294,JCYJ20200109141222892Startup grant from Southern University of Science and Technology。
文摘Photoacoustic(PA)microscopy is being increasingly used to visualize the microcirculation of the brain cortex at the micron level in living rodents.By combining it with long-term cranial window techniques,vasculature can be monitored over a period of days extending to months through a field of view.To fulfill the requirements of long-term in vivo PA imaging,the cranial window must involve a simple and rapid surgical procedure,biological compatibility,and sufficient optical-acoustic transparency,which are major challenges.Recently,several cranial window techniques have been reported for longitudinal PA imaging.Here,the development of chronic cranial windows for PA imaging is reviewed and its technical details are discussed,including window installation,imaging quality,and longitudinal stability.
文摘Miniaturized sound generators are attractive to realize intriguing functions.Thermoacoustic device’s application is seriously limited due to the frequency-doubling phenomenon.To address this issue,photoacoustic sound generator is considered as a promising alternative.Here,based on vertical single-wall carbon nanotubes(CNTs)array,we introduce a photoacoustic sound generator with internal nano-Helmholtz cavity.Different from traditional device that generates sound by periodically heating up the open space air around material,this sound generator produces an audio signal by forming a forced vibration of the air inside the CNTs.Interestingly,anomalous photoacoustic behavior is observed that the sound pressure level(SPL)curve has a resonance peak,the corresponding frequency of which is inversely proportional to the CNTs array’s height.Furthermore,the energy conversion efficiency of this photoacoustic device is 1.64 times as large as that of a graphene sponge-based photoacoustic device.Most importantly,this device can be employed for music playing,bringing a new clew for the development of musical instruments in the future.
