If the treatment area size is small, what is the expected consequence, according to the material?

If the treatment area size is small, what is the expected consequence, according to the material?

• A. The waves spread out and do not penetrate
• B. The waves become more intense
• C. The waves maintain penetration
• D. The waves accelerate

Answer: (A)

When the treatment area is small, the ultrasound beam exits through a narrow aperture and tends to diverge more as it travels. This beam spreading distributes the energy over a wider surface, reducing the energy density at depth, so penetration becomes poor. In other words, the waves spread out and don’t penetrate as effectively. The other options don’t fit because increasing the beam’s size or focusing would increase or preserve penetration, not reduce it; and wave speed is determined by the medium, not by the size of the treatment area, so the waves don’t merely accelerate.

When the treatment area is small, the ultrasound beam exits through a narrow aperture and tends to diverge more as it travels. This beam spreading distributes the energy over a wider surface, reducing the energy density at depth, so penetration becomes poor. In other words, the waves spread out and don’t penetrate as effectively.

The other options don’t fit because increasing the beam’s size or focusing would increase or preserve penetration, not reduce it; and wave speed is determined by the medium, not by the size of the treatment area, so the waves don’t merely accelerate.