Radiology
The branch of medicine that uses ionizing and nonionizing radiation for the diagnosis and treatment of disease.
Historically, radiology involved the use of ionizing radiation including X rays for the diagnosis of disease and X rays and gamma rays for the treatment of disease.
More recently, radiology has also embraced the use of radioactive isotopes and of nonionizing radiation such as ultrasound waves and nuclear magnetic resonance imaging (MRI).
Radiology is also known as roentgenology after Wilhelm Conrad Roentgen who discovered X-rays in 1895.