Acoustic characterization of echogenic liposomes: Frequency-dependent attenuation and backscatter

Destruction of Recombinant Tissue Plasminogen Activator (rtPA) -Loaded Echogenic Liposomes under Dual Frequency Sonication

Background:Echogenic liposomes (ELIPs) encapsulate drugs and gas bubbles within lipid vesicles. The destruction of ELIPs in response to MHz and kHz ultrasound waves has been studied previously. Applying ultrasound above a certain threshold causes encapsulated gas bubbles destruct rapidly by fragmentation or more slowly by acoustically driven diffusion. This study compares the d...

Roughness characterization of porous soil with acoustic backscatter.

The use of acoustics to determine the pore properties of soils, such as porosity, permeability, and tortuosity, is well established. A theoretical surface impedance and complex bulk wavenumber was developed by K. Attenborough for porous media that incorporated the soil pore properties as parameters [J. Acoust. Soc. Am. 73, 785-799 (1983)]. Acoustic level difference measurements were used as a n...

Echogenic Liposomes for Nitric Oxide Delivery and Breast Cancer Treatment

Destruction thresholds of echogenic liposomes with clinical diagnostic ultrasound.

Echogenic liposomes (ELIP) are submicron-sized phospholipid vesicles that contain both gas and fluid. With antibody conjugation and drug incorporation, these liposomes can be used as novel targeted diagnostic and therapeutic ultrasound contrast agents. The utility of liposomes for contrast depends upon their stability in an acoustic field, whereas the use of liposomes for drug delivery requires...

Causality Analysis of Frequency Dependent Wave Attenuation

The work is inspired by thermo-and photoacoustic imaging, where recent efforts are devoted to take into account attenuation and varying wave speed parameters. In this paper we derive and analyze causal equations describing propagation of attenuated pressure waves. We also review standard models, like frequency power laws, and the thermo-viscous equation and show that they lack causality in the ...