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Changhui Li
Ph.D., Associate Professor
Department of Biomedical Engineering, Peking University
  • Office Add: Room A535, Beida Hospital Building
  • Office Tel: +86-10-62767894
  • Lab Add: Room A533, Beida Hospital Building
  • Lab Tel: +86-10-62755242
  • Fax: +86-10-62767894
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B.S., Technical Physics, Beijing University, Beijing

M.S., Physics, Beijing University, Beijing

M.S., Physics, Texas A&M University, College Station

Ph.D., Physics, Texas A&M University, College Station

Research Areas

Biomedical Optics, Photoacoustic Tomography, Fluorescence Molecular Tomography

Research Profile

Our team focuses on the development of in vivo optical tomography modalities. Optical imaging has many unique advantages, including non-ionizing, high contrast, fast imaging speed and spectroscopic capability. However, strong light scattering in tissue makes it very challenging for optical methods to image objects deep in tissue.

High-resolution optical imaging methods, such as optical microscopy, can only image targets that are less than 1 mm deep in turbid tissue. We are exploring photoacoustic tomography (PAT) to break through this imaging barrier. PAT is a hybrid imaging modality that combines the optical absorption contrast with the ultrasonic detection. When some tissue, such as blood, absorbs the photon energy from the pulsed laser, it will generate ultrasound due to thermal expansion process. Since ultrasound has a much lower scattering coefficient than that of light, PAT can take advantage of the multi-scattered photons to image deep tissue. We have obtained sub-millimeter resolution when imaging objects over one centimeter deep in tissue. We also use spectroscopic PAT to provide functional imaging for subcutaneous objects.

In addition to PAT, we are engaged in research on fluorescence molecular tomography (FMT). Due to strong light scattering, traditional fluorescence imaging generally only provide 2D information, and the image resolution drops quickly as the depth of the fluorophore increases. Based on the study of photon migration in tissue, FMT quantitively reconstructs the fluorophore in 3D version. We currently focus on developing novel non-contact FMT by using CCD camera to acquire fluorescence signal.

Professional Activities

Guest Associate Editor: Medical Physics (American Association of Physicists in Medicine)

Selected Recent Publications

1.Chi Zhang, Changhui Li, and Lihong V. Wang, "Fast and robust deconvolution-based image reconstruction for photoacoustic tomography in circular geometry: experimental validation," IEEE Photonics J. (2010) 57-66.
2.Zhun Xu, Changhui Li, and Lihong V. Wang, “Photoacoustic tomography of water in phantom and tissue,” Journal of Biomedical Optics 15 (2010) 036019.
3.Zijian Guo, Changhui Li, Liang Song, and Lihong V. Wang, “Compressed sensing in photoacoustic tomography in vivo,” Journal of Biomedical Optics 15 (2010) 021311.
4.Changhui Li and Lihong V. Wang, “Real-time photoacoustic tomography of cortical hemodynamics in small animals,” Journal of Biomedical Optics Letters 15 (2010) 010509.  
5.Changhui Li and Lihong V. Wang, “Photoacoustic tomography and sensing in biomedicine,” Physics in Medicine and Biology (2009) R59 –R97.  (Topical review article)
6.Changhui Li and Lihong V. Wang, “Photoacoustic tomography of a mouse cerebral cortex with a high-numerical-aperture-based virtual point detector,” Journal of Biomedical Optics 14 (2009) 024047.
7.Changhui Li and Lihong V. Wang, “High-numerical-aperture-based virtual point detectors for photoacoustic tomography,” Applied Physics Letters 93, 033902 (2008)
8.Manojit Pramanik, Geng Ku, Changhui Li, and Lihong V. Wang, "Design and evaluation of a novel breast cancer detection system combining both thermoacoustic (TA) and photoacoustic (PA) tomography," Medical Physics 35 (6) (2008) 2218–2223.
9.Changhui Li, Geng Ku, and Lihong V. Wang, “Negative lens concept for photoacoustic tomography,” Physical Review E 78 (2008) 021901.
10.Changhui Li, Manojit Pramanik, Geng Ku, and Lihong V. Wang, “Image distortion in thermoacoustic tomography caused by microwave diffraction,” Physical Review E 77 (2008) 031923.
Book and Book Chapters:
Changhui Li, Chulhong Kim, and Lihong V. Wang, “Photoacoustic Tomography and Ultrasound-Modulated Optical Tomography,” in Handbook of Biomedical Optics, David A. Boas, Constantinos Pitris, and Nimmi Ramanujam  Ed. (CRC Press, Boca Raton, 2011).