Ultrasound Contrast Agents: Fabrication, size distribution and visualization

Ultrasound contrast agents composed of micro-bubble filled with gas are introduced to increase the backscattered power from blood. Their intravenously injection results in the improved contrast in the images. The aim of this master thesis project is to manufacture MB suspension at varied temperature and shear forces and to inspect the size distribution and concentration of the PVA-shelled micro-bubble with standard methods according to the developed protocol. A pulser-receiver (Panametrics PR 5072) setup combined with two transducers (2.25 MHz and 5 MHz) was used to investigate the backscattered enhancement of the micro-bubble suspension. Images were collected with transmission optical microscope (OLYMPUS IX71) with the aid of counting chamber. The diameter and concentration of the micro-bubbles were analyzed by Image J. The pulser-receiver setup was used to test the acoustic response. The mean diameter of micro-bubbles was from 2.03 to 4.38 μm with a standard deviation between 0.40 and 1.12 μm and the micro-bubble concentration varied from 0.07×10 to 5.22×10 MBs/ml. The enhancement of the ultrasound backscattered power was greater than 20 dB or even reached 30 dB when the energy was increased.