ARDMS Ultrasound Physics & Instrumentation Practice Exam

What is the commonly accepted speed of sound in soft tissue?

1. 1430 m/s

2. 1540 m/s

3. 1540 km/s

4. 1300 m/s

The correct answer is: 1540 m/s

The commonly accepted speed of sound in soft tissue is 1540 m/s. This value is crucial for various applications in ultrasound imaging, as it helps determine how sound waves propagate through different materials in the body. Understanding this speed allows for precise calculations of distance based on the time it takes for ultrasound waves to return to the transducer after reflecting off tissue interfaces. Other values mentioned, such as 1430 m/s, 1300 m/s, and 1540 km/s, are not utilized as the standard speed of sound in soft tissue under typical conditions. The slightly lower values, such as 1430 m/s and 1300 m/s, might represent sound propagation in different mediums or specific tissues that are not reflective of soft tissue as a whole. Additionally, 1540 km/s is significantly faster than the actual speed of sound in any biological tissue, as it suggests speeds that are far beyond the physical limitations of sound transmission. Thus, the value of 1540 m/s serves as the benchmark for ultrasound calculations within the field.