Pulses of sound directed at the patient and the returning echoes are recorded to create images of specific portions of the body.

Pulses of sound directed at the patient and the returning echoes are recorded to create images of specific portions of the body.

• A. X-ray
• B. MRI
• C. Ultrasound
• D. CT scan

Answer: (C)

Imaging with sound waves that bounce back echoes is the key idea. In ultrasound, a transducer sends high-frequency sound pulses into the body and then listens for the echoes that return from tissues. By measuring how long the echoes take to return and how strong they are, the machine builds images of specific areas—like organs, blood vessels, or a fetus—in real time. This method is nonionizing and particularly good for soft tissues, making it distinct from X-ray or CT (which use ionizing radiation) and from MRI (which uses magnetic fields). The echo-based approach described is precisely what ultrasound uses to create images.

Imaging with sound waves that bounce back echoes is the key idea. In ultrasound, a transducer sends high-frequency sound pulses into the body and then listens for the echoes that return from tissues. By measuring how long the echoes take to return and how strong they are, the machine builds images of specific areas—like organs, blood vessels, or a fetus—in real time. This method is nonionizing and particularly good for soft tissues, making it distinct from X-ray or CT (which use ionizing radiation) and from MRI (which uses magnetic fields). The echo-based approach described is precisely what ultrasound uses to create images.