Ultrasound

Review of Terms:

Frequency - refers to the rate at which something repeats, such as the number of times a sound wave oscillates per second

• Frequency is measured Hz

• One Hz represents one cycle per second

Frequency is inversely proportional to wavelength

• Higher Frequency waves have shorter wavelengths

Biophysics of Ultrasound - Piezoelectric properties

• Sound waves created by an alternating current being applied to a crystal with piezoelectric properties

• Crystal expands and contracts with changing polarity of the current, with expansion it compresses materials in front of it, and with contraction it rarifies

• Attenuation - The decrease in ultrasound intensity as it travels through tissue

• Impacted by: Absorption; Reflection; Refraction

Properties