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Photoacoustic Tomography: From Bench to Bedside


Lin, Li (2020) Photoacoustic Tomography: From Bench to Bedside. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/1DGY-T168.


Photoacoustic imaging (PAI) is an emerging imaging modality that shows great potential for preclinical research and clinical practice. As a hybrid technique, PAI uniquely combines the advantages of optical excitation and of acoustic detection. Optical absorption provides a rich contrast mechanism from either endogenous chromophores or exogenous contrast agents. Because ultrasound scatters much less than light in tissue, PAI generates high-resolution images in both the optical ballistic and diffusive regimes, overcoming the limitations imposed by light scattering in deep biological tissues. PAI has led to a variety of exciting discoveries and applications from laboratory research to clinical patient care.

To translate photoacoustic technology from the bench to the bedside, this thesis focuses on efforts to increase the imaging depth, provide clinically useful information (i.e., relevant imaging contrast), reduce system size, and improve system reliability. Assisted by powerful pulsed lasers and advanced data acquisition circuits, modern PAI has achieved applications such as functional imaging of the whole rat brain, revealing detailed angiography and functional connectivity at high spatiotemporal resolution. The advancement of deep imaging in small animal PAI has been transferred to human breast and brain imaging, showing early promise for clinical practice. To further extend the imaging depth and provide dielectric imaging contrast, microwave-based thermoacoustic tomography has been demonstrated in vivo. To map further physiological contrasts, spectroscopic PAI has been performed to image the oxygenation states of hemoglobin and myoglobin. In addition to the effort towards deep penetration and multiple contrasts, benchtop photoacoustic microscopy has been minimized to a handheld probe for human skin imaging. As a rapidly evolving imaging technology, PAI is being translated from the bench to the bedside and promises exciting and useful clinical applications.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Photoacoustic imaging
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Medical Engineering
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Wang, Lihong
Thesis Committee:
  • Tai, Yu-Chong (chair)
  • Shapiro, Mikhail G.
  • Yang, Changhuei
  • Wang, Lihong
Defense Date:4 December 2019
Non-Caltech Author Email:linlijames (AT)
Funding AgencyGrant Number
National Institutes of Health (NIH)DP1 EB016986
National Institutes of Health (NIH)R01 CA186567
National Institutes of Health (NIH)R01 EB016963
National Institutes of Health (NIH)R01 EB010049
National Institutes of Health (NIH)R01 CA159959
Record Number:CaltechTHESIS:12092019-113537728
Persistent URL:
Related URLs:
URLURL TypeDescription adapted for Ch. 2 adapted for Ch. 2 adapted for Ch. 3 adapted for Ch. 5 adapted for Ch. 6 adapted for Ch. 7 adapted for Ch. 8
Lin, Li0000-0002-0517-8436
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13600
Deposited By: Li Lin
Deposited On:20 Dec 2019 18:01
Last Modified:08 Nov 2022 00:18

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