What happens to a 1 MHz ultrasound beam when it travels through tissue?

What happens to a 1 MHz ultrasound beam when it travels through tissue?

• A. Spreads out and dissipates
• B. Penetrates and concentrates energy at depth
• C. Remains the same intensity
• D. Is fully absorbed at the surface

Answer: (A)

As ultrasound travels through tissue, the beam doesn’t stay tight and constant. It spreads out due to diffraction and loses energy as it is absorbed and scattered, so its intensity drops with depth. A 1 MHz beam will still penetrate, but that energy is dissipated as it travels, rather than staying strong or concentrating at a specific depth. It isn’t fully absorbed at the surface, and it isn’t kept at the same intensity or focused deeper in the tissue. So the best description is that the beam spreads and dissipates as it moves through tissue.

As ultrasound travels through tissue, the beam doesn’t stay tight and constant. It spreads out due to diffraction and loses energy as it is absorbed and scattered, so its intensity drops with depth. A 1 MHz beam will still penetrate, but that energy is dissipated as it travels, rather than staying strong or concentrating at a specific depth. It isn’t fully absorbed at the surface, and it isn’t kept at the same intensity or focused deeper in the tissue. So the best description is that the beam spreads and dissipates as it moves through tissue.