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Published on: July 26, 2016
Photoacoustic Doppler effect from flowing small light-absorbing particles
Hui Fang1, Konstantin Maslov, Lihong V Wang
1Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Dr., St. Louis, Missouri 63130, USA.
Physical Review Letters
|November 13, 2007
Summary
Researchers observed a photoacoustic Doppler shift in flowing carbon particles, which is half that of ultrasound Doppler. This discovery enables new photoacoustic Doppler flowmetry for imaging deep blood flow in tissues.
Area of Science:
- Physics
- Biomedical Engineering
- Optics
Background:
- Photoacoustic imaging combines light absorption and ultrasound detection.
- Doppler ultrasound is widely used for blood flow measurement.
- Measuring low-speed flow in scattering media remains challenging.
Purpose of the Study:
- To investigate the photoacoustic Doppler shift in a flowing particle suspension.
- To explore the potential of photoacoustic Doppler flowmetry for biological applications.
Main Methods:
- Flowing suspension of micrometer-scale carbon particles.
- Photoacoustic detection of Doppler shift.
- Theoretical prediction and experimental observation.
Main Results:
- Observed photoacoustic Doppler shift in flowing particles.
- Doppler shift was half of that in Doppler ultrasound.
- Shift was independent of laser illumination direction.
Conclusions:
- A novel physical phenomenon, the photoacoustic Doppler shift, has been demonstrated.
- This phenomenon forms the basis for photoacoustic Doppler flowmetry.
- Potential applications include detecting fluid flow in scattering media and deep microcirculation.
