An x–ray is a test in which part of the body is imaged by using low doses of electromagnetic radiation that are reflected on film or fluorescent screens. These images, also known as radiographs or roentgenograms, are used to diagnose and monitor the treatment of various diseases.

X–ray tests are fast and relatively inexpensive. They are usually noninvasive and painless but are sometimes minimally invasive, meaning they may involve injection with a contrast medium (dye) to help highlight internal structures. They are generally safe for people of all ages when used correctly. Medical professionals often perform x–ray exams in the diagnosis of many painful conditions, including:

• Detecting fractures and other trauma to bones
  
  

  

• Assessing sprains and strains
• Locating or checking causes of dental pain
• Screening for osteoporosis

In addition, x–rays are sometimes used to diagnose nonspecific sources of pain, such as:

• Back pain
• Joint pain (e.g., knee or wrist)
• Internal problems (e.g., abdominal pain)
• Head or brain injury
• Chest pain
• Motor, bowel, bladder or sexual problems
• Progressive conditions, such as advanced arthritis

Examinations with x–ray tests explain only a small percentage of the nonspecific pain complaints physicians receive. X–ray results are two dimensional, with the boundaries between internal structures often blurred on x–ray film. X–rays may be useful in determining irregularities in the body but cannot image pain itself. Consequently, results may be misleading or inconclusive in some instances. They are used most effectively for pain diagnosis when they are combined with other assessments (e.g., physical exam) and correlated with specific symptoms.

Other medical tests that combine computer and x–ray technology (e.g., fluoroscopy, CAT scan) may also be used to confirm the source of some types of pain (e.g., back pain, tooth pain). In some cases, a series of x–ray tests over a period of time may also be needed to assess a condition or compare changes.

In addition to their diagnostic roles, x-rays are used at much higher intensity in radiation therapy for cancer.