Optical droplet vaporization of micron-sized perfluorocarbon droplets and their photoacoustic detection

An acoustic and photoacoustic characterization of micron-sized perfluorocarbon (PFC) droplets is presented. PFC droplets are currently being investigated as acoustic and photoacoustic contrast agents and as cancer therapy agents. Pulse echo measurements at 375 MHz were used to determine the diameter, ranging from 3.2 to 6.5 μm, and the sound velocity, ranging from 311 to 406 m/s of nine droplets. An average sound velocity of 379 ± 18 m/s was calculated for droplets larger than the ultrasound beam width of 4.0 μm. Optical droplet vaporization, where vaporization of a single droplet occurred upon laser irradiation of sufficient intensity, was verified using pulse echo acoustic methods. The ultrasonic backscatter amplitude, acoustic impedance and attenuation increased after vaporization, consistent with a phase change from a liquid to gas core. Photoacoustic measurements were used to compare the spectra of three droplets ranging in diameter from 3.0 to 6.2 μm to a theoretical model. Good agreement in the spectral features was observed over the bandwidth of the 375 MHz transducer.

[1]  Michael C. Kolios,et al.  Quantitative measurements of apoptotic cell properties using acoustic microscopy , 2010, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[2]  G A Briggs,et al.  Quantitative acoustic microscopy of individual living human cells , 1993, Journal of microscopy.

[3]  Oliver D Kripfgans,et al.  Delivery of chlorambucil using an acoustically-triggered perfluoropentane emulsion. , 2010, Ultrasound in medicine & biology.

[4]  M. Woydt,et al.  In vivo droplet vaporization for occlusion therapy and phase aberration correction , 2002, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[5]  J W Hunt,et al.  High-frequency ultrasound scattering from microspheres and single cells. , 2005, The Journal of the Acoustical Society of America.

[6]  Ivan Gorelikov,et al.  Single-step coating of mesoporous silica on cetyltrimethyl ammonium bromide-capped nanoparticles. , 2008, Nano letters.

[7]  John A. Rowlands,et al.  Nanoparticle-Tagged Perfluorocarbon Droplets for Medical Imaging , 2008 .

[8]  Jackie Y Ying,et al.  Silica-coated nanocomposites of magnetic nanoparticles and quantum dots. , 2005, Journal of the American Chemical Society.

[9]  Ivan Gorelikov,et al.  Optical droplet vaporization (ODV): Photoacoustic characterization of perfluorocarbon droplets , 2010, 2010 IEEE International Ultrasonics Symposium.

[10]  Gregory D. Scholes,et al.  Colloidal PbS Nanocrystals with Size‐Tunable Near‐Infrared Emission: Observation of Post‐Synthesis Self‐Narrowing of the Particle Size Distribution , 2003 .

[11]  Sun,et al.  Photoacoustic monopole radiation in one, two, and three dimensions. , 1991, Physical review letters.

[12]  Stanislav Emelianov,et al.  Photoacoustic and ultrasound imaging contrast enhancement using a dual contrast agent , 2010, BiOS.

[13]  Frank Stracke,et al.  Gigahertz optoacoustic imaging for cellular imaging , 2010, BiOS.

[14]  Samuel A Wickline,et al.  Temperature dependence of acoustic impedance for specific fluorocarbon liquids. , 2002, The Journal of the Acoustical Society of America.

[15]  J B Fowlkes,et al.  Acoustic droplet vaporization for therapeutic and diagnostic applications. , 2000, Ultrasound in medicine & biology.

[16]  Zhiwei Lu,et al.  Investigation of stimulated Brillouin scattering media perfluoro-compound and perfluoropolyether with a low absorption coefficient and high power-load ability. , 2008, Applied optics.

[17]  R. Jain,et al.  Regulation of transport pathways in tumor vessels: role of tumor type and microenvironment. , 1998, Proceedings of the National Academy of Sciences of the United States of America.