Both external and internal focusing are considered _______ techniques.

Both external and internal focusing are considered _______ techniques.

• A. Dynamic focusing
• B. Adaptive focusing
• C. Progressive focusing
• D. Fixed focusing

Answer: (A)

Dynamic focusing is the idea that the ultrasound beam’s focus can be adjusted to different depths during imaging, so the lateral resolution stays sharp across the image. External focusing uses a lens outside the transducer and internal focusing uses shaping inside the transducer to create a focal point, but both can be incorporated into a system that electronically steers and refocuses the beam as depth changes. The ability to change the focal depth on the fly—rather than having a single fixed focus—defines dynamic focusing. That’s why these methods are categorized as dynamic focusing techniques: they support refocusing for different depths rather than locking the beam to one fixed point. In contrast, fixed focusing would yield optimal resolution only at one depth.

Dynamic focusing is the idea that the ultrasound beam’s focus can be adjusted to different depths during imaging, so the lateral resolution stays sharp across the image. External focusing uses a lens outside the transducer and internal focusing uses shaping inside the transducer to create a focal point, but both can be incorporated into a system that electronically steers and refocuses the beam as depth changes. The ability to change the focal depth on the fly—rather than having a single fixed focus—defines dynamic focusing. That’s why these methods are categorized as dynamic focusing techniques: they support refocusing for different depths rather than locking the beam to one fixed point. In contrast, fixed focusing would yield optimal resolution only at one depth.