Apparatus and method for making gas-filled vesicles of optimal size

Abstract

A method and apparatus for making vesicles suitable for use as contrast agents in which a container containing an aqueous suspension phase and a separate gas phase is shaken using reciprocating motion. The reciprocating motion is produced by a shaker arm that moves the container in two, substantially perpendicular directions, with the motion in the first direction being along an arcuate path. The overall path of the motion occurs in a figure-8 eight pattern. The frequency of shaking is at least approximately 2800 RPM, the length of the shaker arm is at least approximately 6 cm, and the angle through which the shaker arm rotates in the first direction is at least approximately 3.degree.. The total length of travel around the figure-8 pattern is at least 0.7 cm.

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