What is the branch of medicine that uses radiant energy to diagnose and treat patients?

The branch of medicine that uses radiant energy to diagnose and treat patients is called radiology. Radiology involves the use of X-rays, magnetic resonance imaging (MRI), computed tomography (CT), and other forms of radiant energy to create images of the inside of the body. These images are used to diagnose and treat a wide range of medical conditions, including cancer, heart disease, stroke, and bone fractures.