Ultrasound imaging is a _____ procedure that uses _____ to produce images.

• A. Invasive; Ionizing radiation
• B. Noninvasive; Sound waves
• C. Noninvasive; Ionizing radiation
• D. Invasive; Sound waves

Answer: (B)

Ultrasound imaging relies on nonionizing sound waves to create images of the body's internal structures. This makes it noninvasive, since it usually does not require breaking the skin or entering the body. The transducer emits high-frequency sound waves and detects the echoes that bounce back from tissues; those echoes are converted into the image you see. Not using ionizing radiation is a key distinction from X-ray–based methods, which involve radiation exposure. So the best description is a noninvasive procedure that uses sound waves to produce images.