Ultrasonography creates images using which of the following?

Ultrasonography, commonly used in medical imaging, relies on high-frequency sound waves to create images of the inside of the body. This technique involves the emission of sound waves that travel into the body; these waves reflect off tissues and structures and return to the ultrasound machine, which interprets the echoes to generate real-time images.

Using sound waves eliminates exposure to ionizing radiation, making ultrasound a safer option compared to various imaging modalities like X-rays or CT scans. The high frequency of the sound waves—typically 1 to 20 megahertz—allows for capturing detailed images of soft tissues, which is especially beneficial in obstetrics and cardiology.

In contrast, other imaging modalities utilize different mechanisms; for instance, magnetic fields are used in MRI, while ionizing radiation is characteristic of X-rays and CT scans. Electromagnetic waves pertain to modalities like MRI or PET scans but do not apply to ultrasonography. Thus, understanding that ultrasonography specifically relies on high-frequency sound waves is critical for recognizing its role and advantages in medical imaging.