| Autor: |
Roy, R. A., Farny, C. H., Wu, T., Holt, R. G., Murray, T. W. |
| Předmět: |
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| Zdroj: |
AIP Conference Proceedings; 2006, Vol. 838 Issue 1, p225-228, 4p, 1 Graph |
| Abstrakt: |
The utilization of cavitation in high intensity focused ultrasound (HIFU) therapy requires the presence of nucleation sites; nucleation threshold pressures in tissues can exceed 4–5 MPa. We investigate the efficacy of transient vapor cavity generation from laser-illuminated gold nanoparticles as a means for nucleating cavitation. An acrylamide tissue phantom seeded with 82-nm diameter gold particle was exposed to 5 ns pulses from a 532 nm Nd:Yag laser. Acoustic emissions from inertial cavitation were detected by a 15 MHz broadband focused transducer at a laser energy of 0.10 mJ/pulse and a HIFU peak-negative focal pressure as low as 0.92 MPa. In comparison, a peak-negative focal pressure of 4.50 MPa was required to nucleate detectable cavitation without laser illumination. A simple analysis reveals that vapor cavities are formed that grow to the Blake radius, at which point they undergo rapid expansion and collapse. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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