Photoacoustic Thermal Diffusion Flowmetry (PA-TDF) utilizes photothermal heating and photoacoustic temperature monitoring to measure the tissue heat clearance time constants from which blood velocity can be inferred. We extended our study of PA-TDF to tissue-mimicking phantoms with vessels at various diameters, configurations and depths and experimentally verified the relations between the estimated time constants and the vessels and the illuminating beam dimensions. We also demonstrated, for the first time, depth-resolved PA-TDF measurement using tone-burst photoacoustic excitation. The excitation utilized two fiber-coupled 830nm laser diodes, one induced slow temperature oscillations and the other induced the PA excitation.

Date Published: 4 March 2013
PDF: 6 pages
Proc. SPIE 8581, Photons Plus Ultrasound: Imaging and Sensing 2013, 85811O (4 March 2013); doi: 10.1117/12.2000904

Published in SPIE Proceedings Vol. 8581:
Photons Plus Ultrasound: Imaging and Sensing 2013
Alexander A. Oraevsky; Lihong V. Wang, Editor(s)