How is Speed of Sound (SOS) in bone determined?

• A. By measuring the frequency of sound waves
• B. By measuring the speed of sound waves in air
• C. By measuring the speed with which sound waves pass through bone
• D. By determining the amplitude of the sound waves

Answer: (C)

The Speed of Sound (SOS) in bone is determined by measuring the speed with which sound waves pass through bone. This measurement is crucial in bone densitometry because it reflects the density and quality of the bone. When sound waves travel through bone, their velocity is influenced by the bone's physical properties, such as its density and elasticity.

In clinical practice, higher SOS values typically indicate denser, healthier bone, while lower SOS values can suggest conditions like osteopenia or osteoporosis. Therefore, understanding how sound propagates through bone provides valuable insight into its structural integrity.

The other methods described do not directly relate to measuring the sound wave propagation in bone. For instance, measuring the frequency of sound waves does not inform us about their velocity in bone. Similarly, measuring the speed of sound waves in air is fundamentally different from measuring them in a denser medium like bone, where sound travels at a different speed. Lastly, the amplitude of sound waves pertains to the strength or intensity of the waves rather than their speed, which is the key aspect in determining SOS in bone. Thus, measuring the speed of sound waves in bone gives the most relevant and accurate information.