Contrast enhancement in photoacoustic imaging

Sheng Wen Huang, Janet F. Eary, Lingyun Huang, Matthew O'Donnell, Congxian Jia, Shai Ashkenazi

Research output: Chapter in Book/Report/Conference proceedingConference contribution


To increase specific contrast over background absorption in photoacoustic (PA) imaging, absorbing contrast agents can be functionalized to target specific cells. However, contrast may be severely limited because of PA signals from finite intrinsic background absorption. If background signals can be suppressed, the molecular dynamic range of contrast agents can be greatly expanded, enhancing contrast and therefore the sensitivity and specificity of PA imaging. We propose differential-absorption photoacoustic (DAPA) imaging for contrast enhancement based on suppressing undesired objects. A pump beam illuminates the imaged object, changing absorption from ground-state absorption to transient absorption. Conventional PA imaging measures ground-state absorption, while DAPA imaging detects the difference between transient and ground-state absorption by subtracting the conventional PA image from a transient PA image taken after pump beam illumination. When parameters are properly chosen so that a region of interest has finite change in absorption whereas the background has negligible change, the DAPA image will provide high contrast between the region of interest and the background. Finite changes in absorption can be obtained using photoluminescent contrast agents. Two tubes were imaged. One contains a Pt(II) octaethylporphine (PtOEP) dye solution and serves as an object of interest while the other contains an IR-783 (from Sigma-Aldrich) dye solution and serves as an object to suppress. Although the IR-783 tube dominates the conventional PA image, it is significantly overwhelmed by the PtOEP tube in the DAPA image. Analysis on excitation probability suggests that DAPA imaging has the potential to provide sufficient imaging depths for biomedical applications.

Original languageEnglish (US)
Title of host publication2009 IEEE International Ultrasonics Symposium and Short Courses, IUS 2009
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages4
ISBN (Print)9781424443895
StatePublished - 2009
Event2009 IEEE International Ultrasonics Symposium, IUS 2009 - Rome, Italy
Duration: Sep 20 2009Sep 23 2009

Publication series

NameProceedings - IEEE Ultrasonics Symposium
ISSN (Print)1051-0117


Other2009 IEEE International Ultrasonics Symposium, IUS 2009


  • Background suppression
  • Contrast enhancement
  • Optoacoustic
  • Photoacoustic


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