The Basics of Ultrasound Physics

Ultrasound is an imaging modality that uses high frequency sound waves to produce images. The frequency of a wave refers to the number of cycles within a period of time. Specifically, 1 hertz (Hz) is 1 cycle/s. Frequency is inversely related to wavelength such that higher frequency waves have shorter wavelengths. The amplitude of a wave refers to the displacement from baseline to peak or baseline to trough. Figure 2.1 illustrates waves with different frequencies.