National Physical Therapy Examination (NPTE) Practice Exam

What is the most appropriate size of soundhead to use when treating a targeted area size of 12 cm² with ultrasound?

1. 1 cm²

2. 3 cm²

3. 5 cm²

4. 8 cm²

The correct answer is: 5 cm²

When using ultrasound therapy, the effective treatment area is a crucial aspect to consider for achieving the best therapeutic outcomes. The size of the soundhead should be chosen based on the size of the area to be treated and the principle of effective treatment applications. In this scenario, where the targeted area size is 12 cm², the chosen soundhead size must adequately cover the area for effective treatment. A soundhead that is too small may not sufficiently cover the area, leading to ineffective treatment and potentially increasing the time required to administer therapy. A 5 cm² soundhead is appropriate because it provides adequate coverage without being excessively small or large for the targeted area. The size of 5 cm² allows for an effective distribution of ultrasound energy, improving penetration and heating effects while fitting the requirement of treating an area that is larger than the soundhead. Larger soundheads might provide quicker treatment but could lead to overlapping treatment zones and wasted energy, which is not ideal for focused ultrasound therapy. Therefore, the 5 cm² soundhead strikes the right balance for the 12 cm² area, enabling effective, localized treatment without unnecessary overlap.