Medical Content Created by the Faculty of the
Harvard Medical School
Doctors have used x-rays for over a century to see inside the body in order to diagnose a variety of problems, including cancer, fractures, and pneumonia. During this test, you usually stand in front of a photographic plate while a machine sends x-rays, a type of radiation, through your body. Originally, a photograph of internal structures was produced on film; nowadays, the image created by the x-rays goes directly into a computer. Dense structures, such as bone, appear white on the x-ray films because they absorb many of the x-ray beams and block them from reaching the plate. Hollow body parts, such as lungs, appear dark because x-rays pass through them.
Doctors use back x-rays to examine the vertebrae in the spine for fractures, arthritis, or spine deformities such as scoliosis, as well as for signs of infection or cancer. X-rays can be taken separately for the three areas of the spine: the cervical spine (neck), thoracic spine (middle back), and lumbar spine (lower back). Occasionally, doctors x-ray the pelvis to help diagnose the cause of back pain.