An ultrasonic wave traversing a colloidal suspension causes distortion of the charge distributions at the sites of individual colloidal particles producing a voltage known as the ultrasonic vibration potential. We show how imaging of colloidal regions within a body can be carried out using a beam of ultrasound to produce a radio frequency vibration potential. A theory for image formation shows that Fourier transformation of vibration potential signals processed by a mixer and low pass filter gives the spatial distribution of colloid. The salient feature of the method, insofar as medical imaging is concerned, is its contrast mechanism.

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For a more complete description of vibration potential imaging in three dimensions see
V. E.
Gusev
and
G. J.
Diebold
(unpublished).
6.

The analysis here has ignored the effects of reflection of ultrasound at boundaries within the irradiated body.

7.

The colloidal silica Snow Tex (Nisson, Inc., Houston, TX) was an aqueous suspension of 2030nm silica with a particle concentration of 1015cm3.

8.

The wave front in a focused sound beam has curvature which must be taken into account in a precise formulation of the problem.

9.

The colloidal gold (Ted Pella, Inc., Redding, CA) was an aqueous suspension of 100-nm-diam particles, at a concentration of 5×109cm3. India ink (Higgins, Inc., Levenburgh, TN) is an aqueous suspension of carbon with a surfactant added for stability. The colloidal silver was an aqueous suspension of 80-nm-diam particles, at a concentration of 1.1×1010cm3. The salt concentrations were 4M. Production of a vibration potential by these solutions is well known from previous reports in the literature.

10.

Whole canine blood preserved with EDTA.

11.

The resolution of nuclear magnetic resonance imaging is not determined by the wavelength of the radiation employed.

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