TY - GEN
T1 - Contrast enhancement in photoacoustic imaging
AU - Huang, Sheng Wen
AU - Eary, Janet F.
AU - Huang, Lingyun
AU - O'Donnell, Matthew
AU - Jia, Congxian
AU - Ashkenazi, Shai
PY - 2009
Y1 - 2009
N2 - 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.
AB - 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.
KW - Background suppression
KW - Contrast enhancement
KW - Optoacoustic
KW - Photoacoustic
UR - http://www.scopus.com/inward/record.url?scp=77952834537&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77952834537&partnerID=8YFLogxK
U2 - 10.1109/ULTSYM.2009.5441834
DO - 10.1109/ULTSYM.2009.5441834
M3 - Conference contribution
AN - SCOPUS:77952834537
SN - 9781424443895
T3 - Proceedings - IEEE Ultrasonics Symposium
SP - 112
EP - 115
BT - 2009 IEEE International Ultrasonics Symposium and Short Courses, IUS 2009
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 2009 IEEE International Ultrasonics Symposium, IUS 2009
Y2 - 20 September 2009 through 23 September 2009
ER -