Which term describes the greatest intensity during the ultrasound pulse?

• A. Temporal Peak
• B. Temporal Average
• C. Spatial Peak
• D. Spatial Average

Answer: (A)

During a pulsed ultrasound beam, the intensity changes with time, rising to a highest instantaneous value and then dropping again within the pulse. The term that describes that largest instantaneous intensity at the peak moment of the pulse is temporal peak intensity. It represents the maximum power per unit area the tissue experiences during the pulse itself. In contrast, temporal average averages this intensity over the entire pulse duration (including the off-time), so it’s lower than the peak. Spatial terms refer to how intensity is distributed across the beam’s cross-section at a given moment, with spatial peak being the highest value at any location in space, not necessarily the maximum over time. So the greatest intensity during the pulse is the temporal peak.