BOC Domain 4 Treatment and Rehab – Therapeutic Modalities Practice Test

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.