Definition

X-rays are a type of electromagnetic radiation, just like visible light.

An x-ray machine sends individual x-ray waves through the body. The images are recorded on a computer or film.

• Structures that are dense (such as bone) will block most of the x-ray, and will appear white.
• Metal and contrast media (special dye used to highlight areas of the body) will also appear white.
• Structures containing air will be black, and muscle, fat, and fluid will appear as shades of gray.

Alternative Names

Radiography

How the Test is Performed

The test is done in a hospital radiology department or in your health care provider's office. How you are positioned depends on the type of x-ray being done. Several different x-ray views may be needed.

You need to stay still when you are having an x-ray. Motion can cause blurry images. You may be asked to hold your breath or not move for a second or two when the image is being taken.

The following are common types of x-rays:

• Abdominal x-ray
• Barium x-ray
• Bone x-ray
• Chest x-ray
• Dental x-ray
• Extremity x-ray
• Hand x-ray
• Joint x-ray
• Lumbosacral spine x-ray
• Neck x-ray
• Pelvis x-ray
• Sinus x-ray
• Skull x-ray
• Thoracic spine x-ray
• Upper GI and small bowel series
• X-ray of the skeleton

How to Prepare for the Test

Before the x-ray, tell your health care team if you are pregnant or may be pregnant.

You will need to remove all jewelry. Metal can cause unclear images. You may need to wear a hospital gown.

How the Test will Feel

X-rays are painless. Some body positions needed during an x-ray may be uncomfortable for a short time.

Risks

X-rays are monitored and regulated so you get the minimum amount of radiation exposure needed to produce the image.

For most x-rays, your risk for cancer, or if you are pregnant, the risk for birth defects in your unborn baby is very low. Most experts feel that the benefits of appropriate x-ray imaging greatly outweigh any risks.

Young children and babies in the womb are more sensitive to the risks of x-rays. Tell your provider if you think you might be pregnant.

References

Mettler FA. Introduction: an approach to image interpretation. In: Mettler FA, ed. Essentials of Radiology. 4th ed. Philadelphia, PA: Elsevier; 2019:chap 1.

Rodney WM, Rodney JRM, Arnold KMR. Principles of x-ray interpretation. In: Fowler GC, ed. Pfenninger and Fowler's Procedures for Primary Care. 4th ed. Philadelphia, PA: Elsevier; 2020:chap 235.