How is the intensity of ultrasound typically measured?

The intensity of ultrasound is typically measured in watts per square centimeter (W/cm²). This unit represents the power of the ultrasound wave delivered per unit area, which is crucial for understanding the effects of ultrasound in medical imaging and therapy. Measuring intensity in this way allows practitioners to assess the safety and effectiveness of ultrasound applications.

The choice of watts per square centimeter is grounded in the understanding that ultrasound works by converting electrical energy into mechanical energy, which is then transmitted into the tissue. This measurement helps in determining both the energy level of a given ultrasound beam and the potential effects it may have on biological tissues.

Other units provided in the options do not accurately reflect the specific needs for measuring ultrasound intensity. For example, grams per centimeter squared and pounds per square inch relate more to pressure and weight rather than to the energy output of ultrasound. Joules per square meter is a measure of energy density but does not directly correspond to the power aspect relevant in ultrasound intensity. Thus, watts per square centimeter is the standard and most appropriate unit used in sonography.