X-rays are a form of radiation, and in a health care setting, a machine sends particles of light through the body. A computer or special film is used to record the images that are created. Structures that are dense (such as bone) will block most of the x-ray particles, 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.

The test is performed in a hospital radiology department or in the doctor’s office by an x-ray technologist. The positioning of the patient, x-ray machine, and film depends on the type of study and area of interest. Multiple individual views may be requested. Much like photography, motion causes blurry images on radiographs, and thus, patients may be asked to hold their breath or not move during the brief exposure (about 1 second).

Inform the doctor prior to the exam if you are pregnant, may be pregnant, or have an IUD inserted. You will remove all jewelry and wear a hospital gown during the x-ray examination because metal and certain clothing can obscure the images and require repeat studies.

There is no discomfort from x-ray exposure. Patients may be asked to stay still in awkward positions for a short period of time.

During a single radiograph, a small amount of the x-rays pass right through the body. The rest are absorbed by tissues in the body. For the exposures encountered in conventional radiography, the risk of cancer or genetic defects is very low. Most experts feel that this low risk is largely outweighed by the benefits of information gained from appropriate imaging. X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Young children and developing fetuses carried by pregnant women are more sensitive to the risks of x-rays. Women should tell doctors about suspected pregnancy.