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Journal of Biomedical Optics • Open Access

Photoacoustic lifetime imaging for direct in vivo tissue oxygen monitoring
Author(s): Qi Shao; Shai Ashkenazi

Paper Abstract

Measuring the partial pressure of oxygen (pO2) in tissue may provide physicians with essential information about the physiological state of tissue. However, currently available methods for measuring or imaging tissue pO2 have significant limitations, preventing them from being widely used in clinics. Recently, we have reported a direct and noninvasive in vivo imaging modality based on the photoacoustic lifetime which overcomes certain drawbacks of the existing methods. The technique maps the excited triplet state of oxygen-sensitive dye, thus reflecting the spatial and temporal distributions of tissue oxygen. Here, we present two studies which apply photoacoustic lifetime imaging (PALI) to monitor changes of tissue oxygen induced by external modulations. The first study modulates tissue oxygen by controlling the percentage of oxygen a normal mouse inhales. We demonstrate that PALI is able to reflect the change in oxygen level with respect to normal, oxygen-rich, and oxygen-poor breathing conditions. The second study involves an acute ischemia model using a thin thread tied around the hindlimb of a normal mouse to reduce the blood flow. PALI images were acquired before, during, and after the restriction. The drop of tissue pO2 and recovery from hypoxia due to reperfusion were tracked and observed by PALI.

Paper Details

Date Published: 6 March 2015
PDF: 6 pages
J. Biomed. Opt. 20(3) 036004 doi: 10.1117/1.JBO.20.3.036004
Published in: Journal of Biomedical Optics Volume 20, Issue 3
Show Author Affiliations
Qi Shao, Univ. of Minnesota, Twin Cities (United States)
Shai Ashkenazi, Univ. of Minnesota, Twin Cities (United States)

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