Which type of imaging uses radiation exposure?

The correct answer is based on the type of technology and methodologies utilized in imaging techniques. A CT scan, or computed tomography scan, uses ionizing radiation in the form of X-rays to produce detailed images of the body's internal structures. This method involves taking multiple X-ray images from different angles, which are then processed by a computer to create cross-sectional images or 3D representations of organs and tissues.

In contrast, ultrasound imaging uses high-frequency sound waves to create images, making it a radiation-free method. MRI, or magnetic resonance imaging, relies on strong magnetic fields and radio waves to generate images, also avoiding the use of radiation. Therapeutic massage, while beneficial for various health issues, does not involve any imaging or radiation exposure at all. Therefore, the distinguishing factor in the correct answer lies in the unique characteristic of the CT scan utilizing radiation to achieve its imaging capabilities.