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. Author manuscript; available in PMC: 2011 Jul 20.
Published in final edited form as: Ther Deliv. 2010 Dec 1;1(6):819–848. doi: 10.4155/tde.10.66

Figure 2. Pulsed ultrasound.

Figure 2

The center frequency (Hz) of an ultrasound (US) exposure is the inverse of the period of the pressure cycle. The pulse repetition frequency (PRF) (Hz) is the inverse of the pulse repetition period (PRP); (s), which is the time duration between pulses. Pulse duration (PD); (s), is the duration of each pulse. Duty cycle (DC) is the fraction of time the pulsed US is ‘on’, or DC = PD/PRP. The US intensity (W/cm2) is defined as the temporal average power per unit area of an US exposure, and is related to the square of the amplitude of the acoustic pressure (Pascal).