In vivo Photoacoustic Tomography of Total Blood Flow and Potential Imaging of Cancer Angiogenesis and Hypermetabolism
Blood flow is a key parameter in studying cancer angiogenesis and hypermetabolism. Current photoacoustic blood flow estimation methods focus on either the axial or transverse component of the flow vector. However, the Doppler angle (beam-to-flow angle) is needed to calculate the total flow speed, and it cannot always be estimated accurately in practice, especially when the system's axial and lateral resolutions are different. To overcome this problem, we propose a method to compute the total flow speed and Doppler angle by combining the axial and transverse flow measurements. The method has been verified by flowing bovine blood in a plastic tube at various speeds and Doppler angles. The error was experimentally determined to be less than 0.3 mm/s for total flow speed, and less than 15° for the Doppler angle. In addition, the method was tested in vivo on a mouse ear. We believe that the proposed method has the potential to be used for cancer angiogenesis and hypermetabolism imaging.
Additional Information© 2012 SAGE Publications. Received: July 25, 2011; Revised: September 19, 2011; Accepted: October 24, 2011. The authors thank Christopher Favazza, Lidai Wang, and Arie Krumholz for helpful discussions, Zijian Guo for data processing, and Prof. James Ballard for manuscript editing. This research was supported by the National Institutes of Health Grants R01 EB000712, R01 EB008085, R01 CA134539, U54 CA136398, R01 EB010049, R01 CA157277, and 5P60 DK02057933. L.V.W. has a financial interest in Microphotoacoustics, Inc. and Endra, Inc., which, however, did not support this work.
Accepted Version - nihms-338766.pdf