Prof. Pai-Chi Li Profile

Prof. Pai-Chi Li

Professor at National Taiwan Univ

SPIE Involvement:

Conference Program Committee | Author

Publications (38)

Proceedings Article | 20 April 2021 Paper

Elevational motion estimation for 3D ultrasound with machine learning and a speckle generating gel pad

Ching-Yen Lee, U-Wai Lok, Pai-Chi Li

Proceedings Volume 11792, 117920U (2021) https://doi.org/10.1117/12.2590727

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Proceedings Article | 27 February 2019 Paper

Functional calcium imaging using optical-resolution photoacoustic microscopy in a 3D tumor cell culture

Wei-Wen Liu, Sheng-Hong Chen, Pai-Chi Li

Proceedings Volume 10878, 108782G (2019) https://doi.org/10.1117/12.2510936

KEYWORDS: Calcium, Tumors, Imaging systems, Signal detection, 3D image processing, Cancer, Photoacoustic imaging, Photoacoustic spectroscopy, Photoacoustic microscopy, Pulsed laser operation

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Proceedings Article | 19 February 2018 Paper

Dual-wavelength OR-PAM with compressed sensing for cell tracking in a 3D cell culture system

Rou-Xuan Huang, Ying Fu, Wang Liu, Yu-Ting Ma, Bao-Yu Hsieh, Shu-Ching Chen, Mingjian Sun, Pai-Chi Li

Proceedings Volume 10494, 1049462 (2018) https://doi.org/10.1117/12.2289975

KEYWORDS: Image restoration, 3D modeling, Photoacoustic spectroscopy, Compressed sensing, Tumors, Imaging systems, Optical microscopy, Laser irradiation, Optical spheres, 3D acquisition

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Proceedings Article | 15 March 2016 Paper

Cost-effective design of a concurrent photoacoustic-ultrasound microscope using single laser pulses

Wen-Shao Wu, Wei-Wen Liu, Pai-Chi Li

Proceedings Volume 9708, 97081O (2016) https://doi.org/10.1117/12.2214096

KEYWORDS: Imaging systems, Microscopes, Ultrasonography, Photoacoustic spectroscopy, Multilayers, Signal generators, Optical filters, Electronic filtering, Pulsed laser operation, Pulse filters, Semiconductor lasers, Tumors, Absorption

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Proceedings Article | 15 March 2016 Paper

Dual-wavelength optical-resolution photoacoustic microscopy for cells with gold nanoparticle bioconjugates in three-dimensional cultures

Po-Yi Lee, Wei-Wen Liu, Shu-Ching Chen, Pai-Chi Li

Proceedings Volume 9708, 97081N (2016) https://doi.org/10.1117/12.2214037

KEYWORDS: Tumors, 3D modeling, Gold, Absorption, Photoacoustic spectroscopy, 3D image processing, In vitro testing, 3D photoacoustic microscopy, Tissue optics, Nanoparticles

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SPIE Journal Paper | 11 August 2015 Open Access

Concurrent photoacoustic-ultrasound imaging using single-laser pulses

Shi-Yao Hung, Wen-Shao Wu, Bao-Yu Hsieh, Pai-Chi Li

JBO, Vol. 20, Issue 08, 086004, (August 2015) https://doi.org/10.1117/12.10.1117/1.JBO.20.8.086004

KEYWORDS: Multilayers, Signal generators, Absorption, Imaging systems, Thin films, Optical filters, Image filtering, Laser energy, Transducers, Microrings

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Proceedings Article | 11 March 2015 Paper

Triggered vaporization of gold nanodroplets for enhanced photothermal therapy

Shu-Wei Liu, Wei-Wen Liu, Pai-Chi Li

Proceedings Volume 9323, 93232C (2015) https://doi.org/10.1117/12.2078234

KEYWORDS: Ultrasonography, Cavitation, Gold, Nanoparticles, Dual energy imaging, Laser irradiation, Tumors, Nanodroplets, In vitro testing, Acoustics

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Proceedings Article | 3 March 2014 Paper

Optical generation of narrowband high frequency ultrasound

Shi-Yao Hung, Bao-Yu Hsieh, Pai-Chi Li

Proceedings Volume 8943, 89432Z (2014) https://doi.org/10.1117/12.2039290

KEYWORDS: Multilayers, Ultrasonography, Signal generators, Pulsed laser operation, Absorption, Image fusion, Photoacoustic spectroscopy, Imaging systems, Signal detection, Laser energy

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Proceedings Article | 4 March 2013 Paper

Enhanced delivery of gold nanoparticles by acoustic cavitation for photoacoustic imaging and photothermal therapy

Yu-Hsin Wang, Ai-Ho Liao, Jia-Yu Lin, Cheng-Ru Lee, Cheng-Ham Wu, Tzu-Min Liu, Churng-Ren Wang, Pai-Chi Li

Proceedings Volume 8581, 858123 (2013) https://doi.org/10.1117/12.2005870

KEYWORDS: Gold, Ultrasonography, Nanoparticles, Cavitation, Tumors, Photoacoustic spectroscopy, Acoustic cavitation, Acoustics, In vitro testing, Nanorods

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Proceedings Article | 4 March 2013 Paper

Acoustic and photoacoustic scattering from transverse isotropic tissues

Yae-lin Sheu, Yi-Ching Ho, Pai-Chi Li

Proceedings Volume 8581, 85814C (2013) https://doi.org/10.1117/12.2005821

KEYWORDS: Photoacoustic spectroscopy, Scattering, Ultrasonics, Transducers, Tissues, Wavefronts, Ultrasonography, Acoustics, Backscatter, Spherical lenses

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SPIE Journal Paper | 3 April 2012 Open Access

Photoacoustic/ultrasound dual-modality contrast agent and its application to thermotherapy

Yu-Hsin Wang, Pai-Chi Li, Ai-Ho Liao, Jui-Hao Chen, Churng-Ren Wang

JBO, Vol. 17, Issue 04, 045001, (April 2012) https://doi.org/10.1117/12.10.1117/1.JBO.17.4.045001

KEYWORDS: Absorption, Temperature metrology, Heat therapy, Gold, Acoustics, Thermography, Biomedical optics, Absorbance, Signal to noise ratio, Nanorods

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Proceedings Article | 23 February 2012 Paper

Signal-to-noise ratio scaled coherence weighting for photoacoustic array imaging

Yu-Hsin Wang, Pai-Chi Li

Proceedings Volume 8223, 822340 (2012) https://doi.org/10.1117/12.909854

KEYWORDS: Signal to noise ratio, Phased arrays, Imaging arrays, Imaging systems, Photoacoustic imaging, Photoacoustic spectroscopy, Interference (communication), Coherence (optics), Acoustics, Image processing

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Proceedings Article | 23 February 2012 Paper

Real-time intravascular ultrasound/photoacoustic imaging system with omni-directional light excitation

Bao-Yu Hsieh, Pai-Chi Li

Proceedings Volume 8223, 822319 (2012) https://doi.org/10.1117/12.909868

KEYWORDS: Imaging systems, Image fusion, Intravascular ultrasound, Transducers, Optical fibers, Image resolution, Real time imaging, Pulsed laser operation, Ultrasonography, Photoacoustic spectroscopy

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Proceedings Article | 23 February 2011 Paper

Thermotherapy with a photoacoustic/ultrasound dual-modality agent

Yu-Hsin Wang, Ai-Ho Liao, Jui-Hao Chen, Yi-Hsien Lee, Churng-Ren Wang, Pai-Chi Li

Proceedings Volume 7899, 78993V (2011) https://doi.org/10.1117/12.875667

KEYWORDS: Heat therapy, Continuous wave operation, Ultrasonography, Absorption, Gold, Spectroscopy, Photoacoustic spectroscopy, Signal to noise ratio, Temperature metrology, Nanoparticles

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Proceedings Article | 19 February 2011 Paper

Photoacoustic generation using coded excitation

Shin-Yuan Su, Pai-Chi Li

Proceedings Volume 7899, 789927 (2011) https://doi.org/10.1117/12.875825

KEYWORDS: Semiconductor lasers, Frequency modulation, Fermium, Signal generators, Signal to noise ratio, Pulsed laser operation, Photoacoustic spectroscopy, Optical filters, Transducers, Electronic filtering

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Proceedings Article | 18 February 2011 Paper

Ultrafast photoacoustic imaging with improved elevational focusing

Yu-Hsin Wang, Pai-Chi Li

Proceedings Volume 7899, 78991J (2011) https://doi.org/10.1117/12.875818

KEYWORDS: Ultrafast imaging, Imaging systems, Transducers, Data acquisition, Image fusion, Ultrasonics, Photoacoustic imaging, Stereoscopy, Ultrasonography, 3D acquisition

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Proceedings Article | 24 February 2010 Paper

Design and synthesis of new gold nanoparticles for enhanced photoacoustic response

Chen-Wei Wei, Carolina Poe, Chi-Meng Chen, Yi-Hsien Lee, Churng-Ren Chris Wang, Pai-Chi Li

Proceedings Volume 7564, 75641S (2010) https://doi.org/10.1117/12.842796

KEYWORDS: Photoacoustic spectroscopy, Gold, Nanoparticles, Particles, Silica, Laser irradiation, Absorption, Nanostructures, Coating, Nanorods

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Gold nanoparticles have been used as contrast agent in photoacoustic imaging to increase the detection sensitivity. For example, gold nanorods (AuNRs) have been used in time-intensity based flow estimation and used as nanoprobes to target cancer cells for early diagnosis and effective treatment. In this study, we aimed at the design and synthesis of a new type of gold nanoparticles with enhanced photoacoustic response. The key hypothesis is to create a nanostructure that allows anisotropic heat release. Specifically, such a structure results in higher heat flux transmitting outwards from the ends of the particle and therefore a greater temperature gradient can be created. To achieve this, a layer of SiO₂ was coated along the longer axis of the gold nanorods, leaving both ends uncovered. These new particles are labeled as AuNR@nu-SiO₂ with non-uniform ("nu") coating of silica. Experiments were performed to demonstrate the enhanced photoacoustic response from AuNR@nu-SiO₂. The optical illumination was delivered by a Ti: Sapphire laser pumped by an Nd:YAG laser. A home-made photoacoustic transducer with a center frequency of 20 MHz detected the resulted acoustic signal. First, new types of particles coated with and without SiO₂ were compared to bare AuNR in order to show the ability of the new nanostructure to enhance photoacoustic response. Second, the shape stability of the new particles was evaluated by measuring the photoacoustic responses versus time after high power laser irradiation. Third, the effect of thickness of SiO₂ of AuNR@nu-SiO₂ ranges from 1 nm to 15 nm was also evaluated. Results show that the mean intensity in photoacoustic image increase about 5 dB for AuNR@nu-SiO₂ compared to bare AuNR. Also, it reveals that the normalized intensity for AuNR drops to below 0.6 while it is mostly larger than 0.7 in the case of AuNR@nu-SiO₂ under pulse laser irradiation. In other words, the new type of nanoparticles is less susceptible to shape transformation. Moreover, it is indicated that the photoaocustic response increases slightly with the thickness of SiO₂ and approach to an maximum response at 9 nm thickness. In short, these new particles can be used to achieve the same level of photoacoustic response with a fewer amount of particles, which means that there is less toxicity.

Proceedings Article | 24 February 2010 Paper

Application of limited-view image reconstruction method to intravascular photoacoustic tomography

Yae-Lin Sheu, Cheng-Ying Chou, Bao-Yu Hsieh, Pai-Chi Li

Proceedings Volume 7564, 75640B (2010) https://doi.org/10.1117/12.843611

KEYWORDS: Photoacoustic spectroscopy, Signal detection, Image restoration, Photoacoustic imaging, Photoacoustic tomography, Sensors, Expectation maximization algorithms, Reconstruction algorithms, Tomography, Interfaces

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Proceedings Article | 24 February 2010 Paper

Photoacoustic image reconstruction for linear scanning geometry using particle swarm optimization method

Yae-Lin Sheu, Weichung Wang, Yukai Hung, Pai-Chi Li

Proceedings Volume 7564, 75640H (2010) https://doi.org/10.1117/12.843612

KEYWORDS: Particle swarm optimization, Photoacoustic spectroscopy, Particles, Signal detection, Spherical lenses, Image restoration, Reconstruction algorithms, Sensors, Radon transform, Photoacoustic imaging

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Proceedings Article | 23 February 2010 Paper

Design and fabrication of an integrated intravascular ultrasound/photoacoustic scan head

Bao-Yu Hsieh, Sung-Liang Chen, Tao Ling, L. Jay Guo, Pai-Chi Li

Proceedings Volume 7564, 756409 (2010) https://doi.org/10.1117/12.843614

KEYWORDS: Transducers, Microrings, Intravascular ultrasound, Ultrasonography, Head, Resonators, Photoacoustic spectroscopy, Waveguides, Image fusion, Polymers

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SPIE Journal Paper | 1 January 2010 Open Access

Enhanced photoacoustic stability of gold nanorods by silica matrix confinement

Leng-Chun Chen, Chen-Wei Wei, Jeffrey Souris, Shih-Hsun Cheng, Chin-Tu Chen, Chung-Shi Yang, Pai-Chi Li, Leu-Wei Lo

JBO, Vol. 15, Issue 01, 016010, (January 2010) https://doi.org/10.1117/12.10.1117/1.3292574

KEYWORDS: Absorption, Silica, Transmission electron microscopy, Gold, Photoacoustic spectroscopy, Tissues, Acquisition tracking and pointing, Medical research, Laser irradiation, Nanorods

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Proceedings Article | 12 February 2009 Paper

Photoacoustic temperature measurements for monitoring of thermal therapy

Shiou-Han Wang, Chen-Wei Wei, Shiou-Hwa Jee, Pai-Chi Li

Proceedings Volume 7177, 71771S (2009) https://doi.org/10.1117/12.809973

KEYWORDS: Continuous wave operation, Nanoparticles, Tumors, Gold, Temperature metrology, Heat therapy, Laser therapeutics, Photoacoustic spectroscopy, Laser irradiation, Nanorods

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Proceedings Article | 12 February 2009 Paper

Design, fabrication, and testing of a dual-band photoacoustic transducer

Jian-Hung Liu, Chen-Wei Wei, Yae-Lin Sheu, Yu-Tsung Tasi, Yu-Hsin Wang, Pai-Chi Li

Proceedings Volume 7177, 717712 (2009) https://doi.org/10.1117/12.809954

KEYWORDS: Photoacoustic spectroscopy, Absorption, Acoustics, Transducers, Tissues, Ultrasonics, Signal detection, Sensors, Gold, Tissue optics

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The absorption coefficients in most biological tissues range from 1 cm-1 to 10 cm-1, which produce photoacoustic signal with peak frequency lower than 5 MHz. However, the lower operating frequencies mean equivalently larger wavelengths, which are incapacitation to resolve smaller objects. In order to obtain the excellent performance of images in both sensitivity and resolution, this study discusses the design and fabrication of the dual frequencies photoacoustic transducer (DFPT) with 36°-rotated, Y-cut lithium niobate (LiNbO3) material. The DFPT had a diameter of 6 mm and comprised two concentric rings of equal area with center frequency of the outer and inner elements as 4.9 MHz and 14.8 MHz, respectively. Moreover, there was a 0.65 mm hole in the DFPT surface for insertion of an optical fiber, which solved conventional light-placing problem. The experiment was performed with an agarose phantom which mixed glass beads with various concentration of black stain to create different optical absorptions. The absorption coefficients of absorbers are 5.6 cm-1 and 11.8 cm-1, respectively. The mean amplitude between the two absorbers differs by 0.5 dB at band 0-5 MHz, while the difference increases to 5.9 dB at band 6-15 MHz. The results show that the DFPT not only provides high ultrasonic resolution but also enhances the contrast based on higher frequency subbands for photoacoustic imaging. The potential of improving the contrast between biological tissues and contrast agent with a significant higher absorption is revealed. In the future, the DFPT will be applied to in vivo investigation with gold nanoparticles. Bioconjugated gold nanoparticles have been used as a photoacoustic contrast agent as well as a molecular probe to target cancer cells in a small animal model. The denseness of targeted gold nanoparticles on tumor results in a higher absorptions, which means higher frequency signals comparing to those of surrounding tissues. Thus, DFPT will assist in recognizing the tumor region for a better diagnosis.

Proceedings Article | 11 March 2008 Paper

In vivo photoacoustic imaging with multiple selective targeting using bioconjugated gold nanorods

Chen-Wei Wei, Chao-Kang Liao, Ying-Yi Chen, Churng-Ren Chris Wang, Ann-Ann Ding, Dar-Bin Shiehd, Pai-Chi Li

Proceedings Volume 6856, 68560J (2008) https://doi.org/10.1117/12.764454

KEYWORDS: Gold, Tumors, Cancer, Nanoprobes, In vivo imaging, Absorption, Photoacoustic imaging, Target detection, Photoacoustic spectroscopy, Nanorods

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Proceedings Article | 28 February 2008 Paper

Photoacoustic wave propagation simulations using the FDTD method with Berenger's perfectly matched layers

Yae-Lin Sheu, Chen-Wei Wei, Chao-Kang Liao, Pai-Chi Li

Proceedings Volume 6856, 685619 (2008) https://doi.org/10.1117/12.764416

KEYWORDS: Photoacoustic spectroscopy, Finite-difference time-domain method, Wave propagation, Biomedical optics, Error analysis, Absorption, Laser irradiation, Acoustics, Computer simulations, Signal attenuation

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SPIE Journal Paper | 1 November 2007 Open Access

Nanorod-based flow estimation using a high-frame-rate photoacoustic imaging system

Chao-Kang Liao, Sheng-Wen Huang, Chen-Wei Wei, Pai-Chi Li

JBO, Vol. 12, Issue 06, 064006, (November 2007) https://doi.org/10.1117/12.10.1117/1.2812704

KEYWORDS: Gold, Photoacoustic imaging, Photoacoustic spectroscopy, Imaging systems, Toxic industrial chemicals, Transducers, Biological research, Absorption, Ultrasonography, Nanorods

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Proceedings Article | 13 February 2007 Paper

Quantitative reconstruction of optical absorption coefficient in backward mode photoacoustic imaging

Chao-Kang Liao, Pai-Chi Li

Proceedings Volume 6437, 64371W (2007) https://doi.org/10.1117/12.701725

KEYWORDS: Absorption, Photoacoustic spectroscopy, Reconstruction algorithms, Photoacoustic imaging, Acoustics, Tissue optics, Transducers, Laser irradiation, Biomedical optics, Tomography

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Proceedings Article | 13 February 2007 Paper

Photoacoustic contrast enhancement using selective subband imaging: experimental results

Chen-Wei Wei, Yae-lin Sheu, Pai-Chi Li

Proceedings Volume 6437, 64370I (2007) https://doi.org/10.1117/12.701745

KEYWORDS: Absorption, Signal detection, Tissues, Image enhancement, Sensors, Photoacoustic spectroscopy, Acoustics, Wave propagation, Tissue optics, Image filtering

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Proceedings Article | 13 February 2007 Paper

Effects of absorption properties on photoacoustic spectral characteristics: numerical analysis

Yae-lin Sheu, Chen-Wei Wei, Pai-Chi Li

Proceedings Volume 6437, 643710 (2007) https://doi.org/10.1117/12.701740

KEYWORDS: Photoacoustic spectroscopy, Absorption, Signal detection, Finite-difference time-domain method, Acoustics, Pulsed laser operation, Wave propagation, Numerical analysis, Biomedical optics, Signal generators

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In photoacoustics, characteristics of the absorbed optical energy are a major determining factor of the characteristics of the photoacoustic signal. In other words, objects with different absorption properties generate photoacoustic signals with different frequency contents. Therefore, effects of absorption properties on photoacoustic spectral characteristics need to be fully understood in order to devise optimal setup for photoacoustic signal detection. The main purpose of this paper is therefore to numerically investigate such effects using a finite-difference time-domain (FDTD) approach. Photoacoustic signal generation can be described by the thermal conduction equation, the continuity and the Navier-Stokes equations, and the state equations in the system. To reduce computational and storage requirements, an axis-symmetrical cylindrical coordinate system with the z-axis parallel to the laser irradiation direction is adopted in our study. Moreover, the MacCormack scheme, which is fourth-order accurate in space and second-order accurate in time, and the first-order Mur absorbing boundary conditions are introduced to implement the FDTD code. The absorption coefficient range from 1cm^-1 to 100 cm^-1 and the signals are detected in forward modes. Results show that the peak frequency of the signal with absorbing coefficient 1cm^-1, 10cm^-1, 20cm^-1, 30cm^-1, 50cm^-1, and 100 cm^-1 is 2.4MHz, 2.4MHz, 4.2MHz, 4.8MHz, 6MHz, and 7.8MHz when detected forwardly. Note that although the peak acoustic frequency increases with the absorption coefficient, but the linear relationship between the two parameters does not hold. The results also imply that photoacoustic image contrast can be improved by properly selecting the receiver signal bandwidth. Assuming two objects with absorption coefficient of 10cm^-1 and 100cm^-1, respectively, it is estimated that a 11.34dB contrast improvement is achievable in the forward mode, while a 8.13dB improvement is possible in the backward mode.

Proceedings Article | 6 March 2006 Paper

A high frame rate photoacoustic imaging system and its applications to perfusion measurements

Chao-Kang Liao, Sheng-Wen Huang, Chen-Wei Wei, Pai-Chi Li

Proceedings Volume 6086, 60860S (2006) https://doi.org/10.1117/12.646196

KEYWORDS: Photoacoustic spectroscopy, Imaging systems, Gold, Photoacoustic imaging, Laser energy, Toxic industrial chemicals, Ultrasonography, Transducers, Data acquisition, Nanorods

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Proceedings Article | 6 March 2006 Paper

Single-energy wash-in photoacoustic blood flow measurements using shape transitions of gold nanorods

Chen-Wei Wei, Sheng-Wen Huang, Ya-Chin Chiou, Cheng-Dah Chen, Churng-Ren Chris Wang, Pai-Chi Li

Proceedings Volume 6086, 60860L (2006) https://doi.org/10.1117/12.645272

KEYWORDS: Gold, Toxic industrial chemicals, Absorption, Photoacoustic spectroscopy, Ultrasonics, Laser irradiation, Transducers, Blood circulation, Acoustics, Nanorods

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Proceedings Article | 6 March 2006 Paper

Multiple targeting in photoacoustic imaging using bioconjugated gold nanorods

Pai-Chi Li, Chen-Wei Wei, Chao-Kang Liao, Cheng-Dah Chen, Kuei-Chen Pao, Churng-Ren Chris Wang, Ya-Na Wu, Dar-Bin Shieh

Proceedings Volume 6086, 60860M (2006) https://doi.org/10.1117/12.645248

KEYWORDS: Gold, Absorption, Nanoparticles, Proteins, Cancer, Photoacoustic spectroscopy, Molecules, Nanoprobes, Photoacoustic imaging, Nanorods

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Cancer cells presented altered surface molecules to encourage their growth and metastasis. Expression of oncogeneic surface molecules also play important roles in the prediction of clinical outcome and treatment response of anti-cancer drugs. It is thus conceivable that imaging of cancer lesions while simultaneously obtaining their pathogenic information at molecular level of as many oncogenic proteins as possible is of great clinical significance. Gold nanoparticles have been used as a contrast agent for photoacoustic imaging. In addition, gold nanoparticles can be bioconjugated to probe certain molecular processes. An intriguing property of gold nanoparticles is its ability to tailor its optical properties. For example, size effects on the surface plasmon absorption of spherical gold nanoparticles have shown that the peak optical absorption red-shifts with the increasing particle size. In addition, the optical absorption spectrum of cylindrical gold nanoparticles (i.e., gold nanorods) exhibits a strong absorption band that is directly related to the aspect ratio. With these unique characteristics, selective targeting can be achieved in photoacoustic molecular imaging. Specifically, gold nanorods with different aspect ratios can be bioconjugated to different antibodies. Multiple targeting and simultaneous detection can then be achieved by using laser irradiation at the respective peak optical absorption wavelength. In this study, photoacoustic multiple targeting using gold nanorods is experimentally demonstrated. We have chosen Her2 and CXCR4 as our primary target molecule as Her2 expression is associated with growth characteristics and sensitivity to Herceptin chemotherapy. On the other hand, CXCR4 expression predict the organ-specific metastatic potential of the cancer cells for clinical intervention in advance. Monoclonal antibody (mAb) against Her2/neu was conjugated to nanorods with several different aspect ratios. The agarose gel is suitable for photoacoustic signal acquisition. A wavelength tunable Ti-Sapphire laser was used for laser irradiation and a 1 MHz ultrasound transducer was used for acoustic detection. The optical wavelength of the laser was tuned between 800 nm and 940 nm, corresponding to gold nanorods of an aspect ratio ranging from 3.7 to 5.9. The results clearly show the potential of photoacoustic molecular imaging with multiple targeting in revealing different oncogene expression levels of the cancer cells.

Proceedings Article | 25 April 2005 Paper

Optoacoustic imaging with improved synthetic focusing

Chao-Kang Liao, Meng-Lin Li, Pai-Chi Li

Proceedings Volume 5697, (2005) https://doi.org/10.1117/12.591052

KEYWORDS: Signal to noise ratio, Transducers, Scattering, Tissue optics, Biomedical optics, Ultrasonography, Acoustics, Image resolution, Image quality, Tissues

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Proceedings Article | 25 April 2005 Paper

Time-intensity based optoacoustic flow measurements with gold nanoparticles

Pai-Chi Li, Chen-Wei Wei, Chao-Kang Liao, Hsiao-Chien Tseng, Yen-Ping Lin, Chia-Chun Chen

Proceedings Volume 5697, (2005) https://doi.org/10.1117/12.591106

KEYWORDS: Nanoparticles, Gold, Toxic industrial chemicals, Imaging systems, Blood circulation, Ultrasonography, Absorption, Nd:YAG lasers, Ultrasonics, Transducers

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Proceedings Article | 12 April 2005 Paper

Vector velocity estimation in swept-scan mode using a K-space approach

Geng-Shi Jeng, Pai-Chi Li

Proceedings Volume 5750, (2005) https://doi.org/10.1117/12.595279

KEYWORDS: Transducers, Doppler effect, Error analysis, Point spread functions, Spatial frequencies, Ultrasonography, Motion models, Data acquisition, Solids, Imaging systems

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Proceedings Article | 23 May 2003 Paper

Contrast-based flow measurements using both inflow and outflow time-intensities

Chih-Kuang Yeh, Pai-Chi Li

Proceedings Volume 5035, (2003) https://doi.org/10.1117/12.479878

KEYWORDS: Toxic industrial chemicals, Brain, Ultrasonics, Acoustics, Time metrology, Tissues, Capillaries, Solids, Mathematical modeling, Ultrasonography

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Proceedings Article | 30 May 2001 Paper

Speckle reduction based on signal decorrelation under different strain states

Pai-Chi Li, Chi-Lin Wu, Mei-Ju Chen

Proceedings Volume 4325, (2001) https://doi.org/10.1117/12.428196

KEYWORDS: Speckle, Tissues, Motion estimation, Spatial resolution, Imaging systems, Point spread functions, Ultrasonography, Data acquisition, Transducers, Scattering

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Proceedings Article | 17 September 1999 Paper

Imaging of inhomogeneities in turbid media

Cho-Ping Chou, Chih-Yu Wang, Jui-Che Tsai, Yean-Woei Kiang, Pai-Chi Li, Chih Chung Yang, Chii-Wann Lin

Proceedings Volume 3863, (1999) https://doi.org/10.1117/12.364387

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Showing 5 of 38 publications

Conference Committee Involvement (17)

Photons Plus Ultrasound: Imaging and Sensing 2025

26 January 2025 | San Francisco, California, United States

Photons Plus Ultrasound: Imaging and Sensing 2024

28 January 2024 | San Francisco, California, United States

Photons Plus Ultrasound: Imaging and Sensing 2023

29 January 2023 | San Francisco, California, United States

Photons Plus Ultrasound: Imaging and Sensing 2022

23 January 2022 | San Francisco, California, United States

Photons Plus Ultrasound: Imaging and Sensing 2021

6 March 2021 | Online Only, California, United States

Photons Plus Ultrasound: Imaging and Sensing 2020

2 February 2020 | San Francisco, California, United States

Photons Plus Ultrasound: Imaging and Sensing 2019

3 February 2019 | San Francisco, California, United States

Photons Plus Ultrasound: Imaging and Sensing 2018

28 January 2018 | San Francisco, California, United States

Photons Plus Ultrasound: Imaging and Sensing 2017

29 January 2017 | San Francisco, California, United States

Photons Plus Ultrasound: Imaging and Sensing 2016

14 February 2016 | San Francisco, California, United States

Photons Plus Ultrasound: Imaging and Sensing 2015

8 February 2015 | San Francisco, California, United States

Photons Plus Ultrasound: Imaging and Sensing 2014

2 February 2014 | San Francisco, California, United States

Photons Plus Ultrasound: Imaging and Sensing 2013

3 February 2013 | San Francisco, California, United States

Photons Plus Ultrasound: Imaging and Sensing 2012

22 January 2012 | San Francisco, California, United States

Photons Plus Ultrasound: Imaging and Sensing 2011

23 January 2011 | San Francisco, California, United States

Photons Plus Ultrasound: Imaging and Sensing 2010

24 January 2010 | San Francisco, California, United States

Photons Plus Ultrasound: Imaging and Sensing 2009

25 January 2009 | San Jose, California, United States

Showing 5 of 17 Conference Committees

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