What does the duty factor represent in ultrasound?

The duty factor in ultrasound is a crucial parameter that quantifies the percentage of time during which the ultrasound system is actively transmitting sound waves as opposed to being in the listening or receiving mode. It is calculated as the ratio of the pulse duration (the time the ultrasound pulse is being sent) to the pulse repetition period (the total time for one complete cycle of sending and receiving the pulse).

A duty factor of 1 (or 100%) means that sound is continuously transmitted without any listening time, while a lower duty factor indicates that sound is transmitted for only a fraction of the entire cycle. This measurement is particularly important in understanding the efficiency of ultrasound imaging and the potential thermal effects related to tissue heating.

In contrast, average frequency relates to how many cycles of the sound wave occur in a second, intensity reflects the power per unit area of the sound waves, and the speed of sound in tissue is the rate at which sound waves propagate through different materials. These parameters are vital in their own right but do not directly represent the concept of duty factor.