Mr. Ao Teng Profile

Ao Teng

at Nanchang Univ

SPIE Involvement:

Author

Publications (20)

Proceedings Article | 14 November 2021 Paper

Study on the light transmission and photothermal conversion of nanosecond laser pulse with brain using multiple physical field coupling

Jiahao Zeng, Ao Teng, Qianxiang Wan, Hongyu Zhang, Shangkun Hou, Xianlin Song

Proceedings Volume 11914, 119140U (2021) https://doi.org/10.1117/12.2612460

KEYWORDS: Tissues, Blood vessels, Brain, Absorption, Pulsed laser operation, Photoacoustic imaging, Photoacoustic spectroscopy, Temperature metrology, Light sources, Blood

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Proceedings Article | 12 September 2021 Paper

Research on the relationship between photothermal effect and wavelength of laser beam in gastric tumor

Yang Zhao, Ao Teng, Jiahao Zeng, Xianlin Song

Proceedings Volume 11867, 118670T (2021) https://doi.org/10.1117/12.2600942

KEYWORDS: Tumors, Tissues, Stomach, Laser tissue interaction, Tissue optics, Absorption, Photoacoustic imaging, Finite element methods, Ultrasonics, Signal processing

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Photoacoustic imaging (PAI) has gradually developed into a new and important imaging technology, which combines the high contrast of optical imaging and the high resolution of ultrasonic imaging to achieve a deeper imaging of biological tissue, and has been widely used in biological imaging. The basic principle of photoacoustic imaging is that a short pulse of laser is used to illuminate biological tissue. As photons pass through biological tissue, some of them are absorbed by biological molecules such as hemoglobin, DNA-RNA, fat, water, melanin and cytochrome. In PAI, the light absorption mechanisms generally include electron absorption, vibration absorption, stimulated Raman absorption and surface plasmon resonance absorption. The absorbed light energy is usually completely converted to heat energy by the non-radiative relaxation of the excited molecules, and the pressure wave caused by the heat energy is transmitted in the tissue to form ultrasonic wave, namely the photoacoustic signal. The photoacoustic signal reconstruction generated by the detection of ultrasonic transducer can be obtained from biological tissue. The absorption of blood in visible band is much higher than that of other tissues (except melanin) to achieve high resolution imaging of blood vessels without exogenous markers. Due to the characteristics of biological tissue, it has different degrees of absorption to different wavelengths of light, resulting in different heat and pressure waves generated, the final received ultrasonic wave is different, which will affect the final image results. Based on the finite element analysis method, this paper establishes four complete coupling modules in COMSOL software: coefficient form partial differential equation module, biological heat transfer module, solid mechanics module and transient pressure acoustic module. By setting different optical parameters to explore the degree of absorption of different light waves by biological tissues, so as to find the best wavelength of light for the experiment.

Proceedings Article | 12 September 2021 Presentation + Paper

Thermal strain between ultrashort laser pulse and tumor using finite element analysis

Jiahao Zeng, Ao Teng, Xianlin Song

Proceedings Volume 11876, 1187608 (2021) https://doi.org/10.1117/12.2596686

KEYWORDS: Tumors, Tissues, Photoacoustic spectroscopy, Photoacoustic imaging, Ultrasonography, Pulsed laser operation, Natural surfaces, Finite element methods, Ultrafast phenomena, Mechanics

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Proceedings Article | 7 September 2021 Poster + Presentation + Paper

Visualization of the relationship between photothermal effect and wavelength in gastric tumor based on finite element analysis

Yang Zhao, Ao Teng, Xianlin Song

Proceedings Volume 11815, 118150L (2021) https://doi.org/10.1117/12.2592079

KEYWORDS: Tumors, Tissues, Stomach, Laser tissue interaction, Tissue optics, Absorption, Photoacoustic imaging, Finite element methods, Visualization, Ultrasonics

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Proceedings Article | 3 August 2021 Presentation + Paper

Visualization of the optoacoustic effect of ultrashort laser pulse using finite element method

Jiahao Zeng, Ao Teng, Xianlin Song

Proceedings Volume 11815, 1181503 (2021) https://doi.org/10.1117/12.2592078

KEYWORDS: Tissues, Picosecond phenomena, Tissue optics, Temperature metrology, Ultrafast phenomena, Pulsed laser operation, Optoacoustics, Light sources

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Proceedings Article | 16 July 2021 Poster + Paper

Research on photoacoustic effect of picosecond laser pulse with tissue based on finite element method

Jiahao Zeng, Rui Wang, Ao Teng, Xianlin Song

Proceedings Volume 11844, 1184416 (2021) https://doi.org/10.1117/12.2601380

KEYWORDS: Picosecond phenomena, Tissue optics, Photoacoustic imaging, Laser tissue interaction, Photoacoustic spectroscopy, Tissues, Temperature metrology, Pulsed laser operation, Light sources, Finite element methods

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Proceedings Article | 18 June 2021 Paper

Optical and thermal interactions of different-wavelength ultrashort laser pulses with breast cancer based on COMSOL

Yuli Li, Ao Teng, Zihao Li, Xianlin Song

Proceedings Volume 11850, 1185007 (2021) https://doi.org/10.1117/12.2599023

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Proceedings Article | 12 April 2021 Presentation + Paper

Visualization of photothermal interaction of Bessel beam with gastric tumor based on COMSOL

Ao Teng, Xianlin Song

Proceedings Volume 11757, 117570G (2021) https://doi.org/10.1117/12.2589663

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In recent years, photoacoustic imaging is a new imaging technology which combines the advantages of high resolution and rich contrast of optical imaging and high penetration depth of acoustic imaging. Therefore, photoacoustic imaging is widely used in biomedical fields, such as brain imaging, tumor detection and so on. As an important branch of photoacoustic imaging, photoacoustic microscopy imaging of optical resolution can reach the submicron level and can meet the needs of multi-scale imaging from cell to tissue. However, the strongly focused Gaussian beam is usually used in the traditional system of photoacoustic microscopy imaging of optical resolution, and so the depth of imaging is small, which makes it difficult to achieve fast imaging of large volume. In order to solve this problem, researchers have proposed many schemes, one of which is to use non-diffracted beams instead of Gaussian beams for imaging. As a nondiffracted beam, Bessel beam is applied to photoacoustic microscopy imaging of optical resolution in this study because it has the characteristic of large depth of field. However, in practice, the cost of building the system of photoacoustic microscopy imaging of optical resolution is high and its structure is complex, so there is an urgent need for the technology of virtual simulation for photothermal simulation analysis of the imaging system. In order to achieve this goal, a virtual simulation platform of photoacoustic microscopy imaging system of Bessel beam based on finite element analysis was built by using simulation software COMSOL Multiphysics. In COMSOL, the Bessel beam realized by compound axicon was constructed and then irradiated the gastric tissue and tumor. The propagation of the Bessel beam in the gastric tissue and tumor was simulated by solving the diffusion equation. And the temperature changes of the gastric tissue and tumor were obtained by solving the equation of biological heat transfer. This study is helpful to understand the propagation of Bessel beam in the gastric tissue and tumor and the interaction between them, and has a certain theoretical significance for biomedical optical imaging.

Proceedings Article | 22 March 2021 Poster + Paper

Simulation study of interaction of Bessel beam with brain based on COMSOL

Xianlin Song, Ao Teng, Jianshuang Wei

Proceedings Volume 11590, 1159015 (2021) https://doi.org/10.1117/12.2592416

KEYWORDS: Photoacoustic microscopy, Imaging systems, Photoacoustic spectroscopy, Optical simulations, Visualization, Photoacoustic imaging, Signal processing, Image resolution, 3D photoacoustic microscopy, 3D image processing

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In recent years, photoacoustic imaging is a new imaging technology which combines the advantages of high resolution and rich contrast of optical imaging and high penetration depth of acoustic imaging. Therefore, photoacoustic imaging is widely used in biomedical fields, such as brain imaging, tumor detection and so on. As an important branch of photoacoustic imaging, photoacoustic microscopy imaging of optical resolution can reach the submicron level and can meet the needs of multi-scale imaging from cell to tissue. However, the strongly focused Gaussian beam is usually used in the traditional system of photoacoustic microscopy imaging of optical resolution, and so the depth of imaging is small, which makes it difficult to achieve fast imaging of large volume. In order to solve this problem, researchers have proposed many schemes, one of which is to use non-diffracted beams instead of Gaussian beams for imaging. As a nondiffracted beam, Bessel beam is applied to photoacoustic microscopy imaging of optical resolution in this study because it has the characteristic of large depth of field. However, in practice, the cost of building the system of photoacoustic microscopy imaging of optical resolution is high and its structure is complex, so there is an urgent need for the technology of virtual simulation for photothermal simulation analysis of the imaging system. In order to achieve this goal, a virtual simulation platform of photoacoustic microscopy imaging system of Bessel beam based on finite element analysis was built by using simulation software COMSOL Multiphysics. In COMSOL, the Bessel beam realized by compound axicon was constructed and then irradiated the human brain tissue. The propagation of the Bessel beam in the brain tissue was simulated by solving the diffusion equation. And the temperature changes of gray matter and blood vessel were obtained by solving the equation of biological heat transfer. This study is helpful to understand the propagation of Bessel beam in human brain and the interaction between them, and has a certain theoretical significance for the optical imaging of human brain.

Proceedings Article | 5 March 2021 Poster + Presentation + Paper

Research on the photon transmission and heat transfer between pulsed laser and human brain based on COMSOL

Ao Teng, Lingfang Song, Jianshuang Wei, Xianlin Song

Proceedings Volume 11642, 116423Y (2021) https://doi.org/10.1117/12.2582921

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Proceedings Article | 5 March 2021 Presentation + Paper

Vortex-beam photoacoustic microscopy for enhancing the depth of field

Cong Liu, Jiahao Zeng, Xianlin Song, Ao Teng, Jianshuang Wei, Lingfang Song, Xueyan Liu

Proceedings Volume 11642, 116423R (2021) https://doi.org/10.1117/12.2589253

KEYWORDS: Photoacoustic spectroscopy, Microrings, Tissues, Signal detection, Resonators, Ultrasonics, Finite element methods, Photoacoustic imaging, Brain, Pulsed laser operation

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Photoacoustic imaging technology is a new functional imaging method in biomedical application field. It is based on photoacoustic effect. It combines the advantages of high resolution and rich contrast of optical imaging with the advantages of high penetration depth of acoustic imaging. It can be used for noninvasive detection of structural, functional and molecular abnormalities in biological tissues, Multi scale information of micro and macro world is detected. Photoacoustic microscope is a micro imaging device based on photoacoustic effect. It can measure the amplitude and phase of photoacoustic signals generated at different positions on the solid surface, so as to determine the optical properties, thermal properties, elasticity or geometric structure of samples. However, the traditional optical resolution photoacoustic microscopy imaging system usually uses strong focused Gaussian beam, which has long imaging time and weak penetrating ability, so it is difficult to achieve fast imaging of solid inner surface. The vortex beam has the characteristics of spiral wavefront structure, circular distribution of light intensity, definite orbital angular momentum and phase singularity. Based on the above characteristics, vortex light has high directivity, wide frequency band and wide bandwidth, which can be used for deep and efficient penetrating imaging of inner surface. In this paper, Matlab is used to generate the ideal and transmitted vortex light phase diagram and spot, and then k-wave simulation software is used to build the virtual simulation platform of vortex photoacoustic microscopy imaging system. In the MATLAB simulation, the vortex light beam irradiates on the vascular cells to image the vascular tissue. The results show that vorticity light has better penetrating ability and faster imaging speed than Gaussian light. This study is helpful to detect the deep structure and properties of vascular cells by using vortex light, and put forward a new idea for the deep fast imaging of solid surface.

Proceedings Article | 5 March 2021 Presentation + Paper

Analysis on the photonic transmission and heat transfer of pulsed laser and breast cancer based on COMSOL multiphysics

Xianlin Song, Yuli Li, Ao Teng, Bo Li, Qiming He, Jinhong Zhang, Aojie Zhao, Zihao Li, Hao Chen, Jianshuang Wei, Lingfang Song, Cong Liu

Proceedings Volume 11622, 116220N (2021) https://doi.org/10.1117/12.2589051

KEYWORDS: Breast, Breast cancer, Tumors, Tumor growth modeling, Photoacoustic imaging, Mammary gland, Laser tissue interaction, Tissues, Oncology, Cancer

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Proceedings Article | 5 March 2021 Presentation + Paper

Spectrum analysis of photoacoustic signal based on COMSOL

Xianlin Song, Shuilong Wang, Xian Li, Ao Teng, Jianshuang Wei, Aojie Zhao, Bo Li, Zihao Li, Qiming He, Jinhong Zhang, Linfang Song

Proceedings Volume 11642, 116423S (2021) https://doi.org/10.1117/12.2589250

KEYWORDS: Photoacoustic spectroscopy, Spectrum analysis, Signal analyzers, Laser tissue interaction, Tumors, Light wave propagation, Light, Diffusion, Ultrasonics, Temperature metrology

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The study of the relationship between the spectral characteristics of the photoacoustic signal and the size, density and shape of the absorber is of great significance to image reconstruction and is of great practical significance to the better application of photoacoustic imaging in the medical field. This paper uses the simulation software COMSOL Multiphysics to design a two-dimensional simulation model based on finite element to study the relationship between the spectral characteristics of the photoacoustic signal and the properties of the absorber. In this study, the model consists of three parts: 1) water layer; 2) short pulse laser source (wavelength of 840nm); 3) gastric tumor tissue. The laser point source is located in the middle of the upper water layer. By solving the diffusion equation and the biological heat equation, respectively, the propagation of light in the water layer and the temperature change in biological tissues are simulated. When the absorber is irradiated by a Gaussian pulsed laser, due to the extremely short time, the absorber can be regarded as adiabatic expansion after absorbing energy, thereby generating ultrasonic waves. Using the finite element analysis method, the complex situation of photoacoustic imaging is transformed into the coupling of multiple physical fields, and the photoacoustic signal is obtained by numerical calculation of partial differential equations. Analyzing the simulation results, it is found that the spectral characteristics of the photoacoustic signal are closely related to the size of the absorber. The relationship obtained in this simulation experiment is: the spectral intercept and the size of the absorber have a power function relationship, the larger the size, the larger the spectral intercept , And the growth rate increases with the increase of the size; the spectral slope and the size of the absorber also have a power function relationship, the larger the size, the smaller the spectral slope, and the rate of change of the slope decreases with the increase of the size. For the relationship between the spectral characteristics and density of the photoacoustic signal, the intercept and slope characteristics are opposite. As the density of the photoacoustic absorber increases, the spectral slope of the photoacoustic signal increases, and the spectral intercept of the photoacoustic signal decreases. The photoacoustic signals and spectrograms of different shapes of absorbers have their own characteristics. The research results in this paper can promote the research of photoacoustic imaging and can better apply photoacoustic imaging in the medical field.

Proceedings Article | 5 March 2021 Poster + Paper

Deconvolution optical-resolution photoacoustic microscope for high-resolution imaging of cerebral vasculature

Xianlin Song, Lingfang Song, Anqing Chen, Jianshuang Wei, Aojie Zhao, Ao Teng

Proceedings Volume 11649, 116491B (2021) https://doi.org/10.1117/12.2588860

KEYWORDS: Deconvolution, Photoacoustic spectroscopy, Image resolution, Tissues, Point spread functions, Photoacoustic imaging, Microscopes, Photoacoustic microscopy, Light scattering, Signal processing

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Photoacoustic imaging is becoming a very promising tool for the research of living organisms. It combines the high contrast of optical imaging and the high resolution of acoustic imaging to realize the imaging of absorption clusters in biological tissues. Since the scattering of ultrasound signals in biological tissues is 2-3 orders of magnitude weaker than the scattering of light in biological tissues, the endogenous absorption difference of tissues is directly used in the imaging process, so photoacoustic imaging has the advantages of deep imaging depth and non-destructive. As an important branch of photoacoustic imaging, photoacoustic microscopy can provide micron-level or even sub-micron-level imaging resolution, which is of great significance for biological research such as blood vessel detection. Since the lateral resolution of the photoacoustic microscopy imaging system depends on the focus of the laser, a higher resolution can be obtained by increasing the numerical aperture of the condenser objective. However, a large numerical aperture usually means a shorter working distance and makes the entire imaging system very sensitive to small optical defects. Therefore, the improvement of resolution through this method will be limited in practical applications. This paper implements a method of using iterative deconvolution to obtain a high-resolution photoacoustic image of the brain. The focal spot of the photoacoustic microscopy is measured to obtain the lateral PSF (point spread function) of the system. Making the measured PSF as the initial system PSF to perform Lucy- Richardson (LR) deconvolution. The image resolution of cerebral vasculature obtained by this method is higher. The full width at half maximum (FWHM) of width of the same cerebral capillaries before and after deconvolution are 7 μm and 3.6 μm, respectively, and the image definition is increased by about 1.9 times. Experiments show that this method can further improve the clarity of photoacoustic images of cerebral capillaries, which lays the foundation for further research on brain imaging.

Proceedings Article | 28 February 2021 Paper

Research on spectrum analysis of photoacoustic signal based on COMSOL platform

Xianlin Song, Shuilong Wang, Xian Li, Ao Teng, Zhouhua Chen, Jianshuang Wei, Aojie Zhao, Bo Li, Zihao Li, Qiming He, Jinhong Zhang, Lingfang Song

Proceedings Volume 11781, 117811O (2021) https://doi.org/10.1117/12.2591387

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The study of the relationship between the spectral characteristics of the photoacoustic signal and the shape and size of the absorber has important practical significance for image reconstruction. Using the commercial finite element simulation software COMSOL Multiphysics, a two-dimensional simulation model based on finite element was designed, which studied the relationship between the spectral characteristics of the photoacoustic signal and the shape and size of the absorber. In this study, the model consists of three parts: 1) water layer; 2) short pulse laser source (wavelength of 840nm); 3) gastric tumor tissue. The laser point source is located in the middle of the upper water layer. Simulate the propagation of light in the water layer by solving the diffusion equation. The temperature changes in biological tissues are obtained by solving the biothermal equation. When the absorber is irradiated by Gaussian pulses, due to the extremely short time, the absorber can be regarded as adiabatic expansion after absorbing energy, thereby generating ultrasonic waves. Using the finite element analysis method, the complex situation of photoacoustic imaging is transformed into the coupling of multiple physical fields and the numerical calculation of partial differential equations to obtain the photoacoustic signal. Fitting the simulation results shows that the spectral characteristics of the photoacoustic signal change regularly with the size of the absorber. The size of the absorber obtained in this paper has a power function relationship with the spectral intercept. The larger the size, the larger the spectral intercept, and the growth rate increases with the increase of the size. The size of the absorber and the spectral slope also have a power function relationship. The slope of the large spectrum is smaller, and the rate of change of the slope decreases as the size increases. At the same time, analyzing the photoacoustic spectrum of absorbers of different shapes also shows that absorbers of different shapes have their own characteristics. This research is helpful to understand the relationship between spectral characteristics and the shape and size of the absorber, and has certain theoretical guiding significance for image reconstruction.