Which unit is commonly associated with measuring amplitude?

The unit commonly associated with measuring amplitude in the context of sonography is decibels (dB). This is because decibels are a logarithmic unit used to express the ratio of a particular measurement to a reference level. In ultrasonography, amplitude relates to the strength of the ultrasound signal, and decibels provide a convenient way to convey changes in amplitude, particularly since these changes can span several orders of magnitude.

Using dB allows sonographers to express the intensity of reflectivity from different tissues and structures within the body in a standardized manner. In clinical practice, when considering the amplitude of sound waves, this unit is crucial for interpreting the imaging results effectively. It reflects not just the strength but also the relative differences in amplitude from one echo to another, which is vital for accurate diagnosis.

The other options pertain to different measurements: millivolts are typically used for electrical signals, Pascals measure pressure which is relevant for understanding wave propagation, and hertz refers to frequency, which measures how many cycles per second a wave completes. These units serve their respective roles but do not directly describe amplitude in the ultrasound context like decibels do.