The type of electromagnetic radiation used in medical imaging is X-rays. X-rays are a form of high-energy radiation that can penetrate body tissues and are commonly used in diagnostic imaging to view the internal structures of the body. The technique involves exposing a part of the body to X-rays, which capture images of bones, organs, and other tissues. This non-invasive method is crucial in diagnosing fractures, infections, and tumors, significantly enhancing the capabilities of modern medicine for patient care.