Which intensity is averaged only during the pulse duration?

The intensity that is averaged only during the pulse duration is termed Pulse Average Intensity. This measurement focuses specifically on the portion of the ultrasound wave where the pulse is actively transmitted, meaning it takes into account the intensity of the ultrasound during the time that the sound wave is present or "on."

By averaging the intensity over the pulse duration, we can obtain a more accurate representation of how much energy is being delivered to the tissue during that specific time. This is particularly relevant in applications like therapeutic ultrasound, where the characteristics of the pulse can significantly influence the treatment's effectiveness.

In contrast, other forms of intensity measurements do not restrict the averaging to just the pulse duration. For example, Temporal Average Intensity encompasses the entire time period, including both the pulse and the listening (or off) periods, while Spatial Average Intensity distributes the intensity over different locations in the beam. Spatial Peak Intensity refers to the maximum intensity found at the point where the ultrasound beam is the strongest but does not average over time. Thus, Pulse Average Intensity provides a focused and relevant measure for evaluating the impact of ultrasound during its active transmission period.