Which intensity measures the power of a sound pulse transmitted over time?

The measure of intensity that reflects the power of a sound pulse transmitted over time is temporal average intensity. This intensity is calculated by taking into account the average power of the ultrasound wave over one complete pulse duration, including both the transmitting (on) and off periods (when the pulse is not being emitted).

Temporal average intensity is particularly important in sonography because it provides a useful way to evaluate the exposure of tissues to the ultrasonic energy over time. This measurement is particularly critical when assessing potential biological effects of ultrasound, as tissues can be affected differently during the periods of transmission compared to when the sound is not being actively emitted.

In contrast, average intensity generally refers to the power averaged over the entire beam, but it doesn't specifically account for time variations within the pulse duration as specifically as temporal average does. Other intensity measures like spatial average intensity focus more on the average power over a specific area rather than time, while pulse intensity is typically concerned with a specific pulse rather than a continuous average over time.

By focusing on the temporal average intensity, practitioners can better understand and manage the energy delivered to tissues, which is vital for patient safety and effective clinical outcomes in sonography.