What term refers to the region of focus where half is located in the near field and half in the far field?

What term refers to the region of focus where half is located in the near field and half in the far field?

• A. Focal Zone
• B. Near Zone
• C. Far Field
• D. Focal Point

Answer: (A)

In ultrasound, the term that describes the region around the focus where the beam remains relatively narrow as it travels toward and past the focal point is the focal zone. This zone spans areas on both sides of the focus, so part of it lies in the near field (before the focus) and part lies in the far field (after the focus). The focal point is a single location of maximum intensity, while the focal zone extends over a length that includes both the approaching (near-field) and departing (far-field) portions. That’s why this term best fits the description of a region containing half near-field and half far-field.

In ultrasound, the term that describes the region around the focus where the beam remains relatively narrow as it travels toward and past the focal point is the focal zone. This zone spans areas on both sides of the focus, so part of it lies in the near field (before the focus) and part lies in the far field (after the focus). The focal point is a single location of maximum intensity, while the focal zone extends over a length that includes both the approaching (near-field) and departing (far-field) portions. That’s why this term best fits the description of a region containing half near-field and half far-field.