X-rays are painless, noninvasive, quick and relatively inexpensive tests that help physicians diagnose and treat medical conditions. While X-rays are the oldest and most frequently used form of imaging, caution should be taken to avoid too much exposure, especially if you think you might be pregnant.
X-rays are a type of radiation made up of electromagnetic waves. X-rays pass through the body and record an image on a special digital recording plate. The digital files can be stored electronically.
Images produced by X-rays vary due to the different absorption rates of different tissues. Calcium in bones absorbs X-rays the most, so bones look white on a film recording of the X-ray image, while soft tissue will appear in shades of gray, and air appears black.
Types of X-rays
Arthrography
This is an X-ray of a joint. It typically uses a type of X-ray that happens in real time called fluoroscopy. A contrast material containing iodine is often injected into the joint.
Bone Density Scans
This test checks the mass or density of bones, and can be used to diagnose osteoporosis.
Chest X-ray
This is the most commonly performed X-ray. It creates images of the heart, lungs, airways, blood vessels, and the bones of the spine and chest. It is used with conditions such as:
- Heart failure and other heart problems
- Lung cancer or other lung problems
- Persistent cough, chest pain or shortness of breath
Coronary Angiography
This test uses dye to show the inside of coronary arteries, which supply blood and oxygen to your heart.
CT Scan
CT scan uses X-rays to produce "sliced" images of the body, which can reveal body structures in great detail.
Cystogram
A cystogram is an X-ray examination of the bladder. The bladder is filled with a contrasting agent during this procedure.
Fluoroscopy
Fluoroscopy uses X-rays to produce images on a monitor in real-time, much like a live broadcast of what's happening inside the body. It displays the movement of a body part, an instrument being inserted into the body or a contrast agent flowing through the body. It is often used to diagnose conditions such as gastroesophageal reflux disease (GERD), heartburn and hiatal hernia.
Lower GI Series
A lower gastrointestinal (GI) series uses X-rays to diagnose problems in the large intestine, which includes the colon and rectum. Patients drink a thick liquid called barium to make the intestines display better on the X-ray. The lower GI series is used to diagnose problems such as:
- Abnormal growths
- Ulcers
- Polyps
- Diverticular disease
- Colon cancer
Mammography
Mammography uses X-rays to look for tumors or suspicious areas in the breasts.
Myelography
Myelography is a special exam of the spinal column. It can check for herniated disks, swelling of the spinal cord or spinal tumors. A contrast dye is often used.
Upper GI Series
An upper gastrointestinal (GI) series uses X-rays to diagnose problems in the esophagus, stomach and the first part of the small intestine (duodenum). During the procedure, barium is swallowed to make the esophagus, stomach and duodenum show up more clearly.
Virtual Colonoscopy
Virtual colonoscopy uses X-rays and computers to produce two-dimensional and three-dimensional images of the colon (large intestine) from the lowest part, the rectum, all the way to the lower end of the small intestine, and displays them on a screen. The procedure diagnoses colon and bowel disease, including polyps, diverticulosis and cancer.
How to Prepare
Most X-rays require no special preparation. Sometimes contrast materials or dyes are used to make certain things stand out to help with a diagnosis. Let your X-ray technologist know if you have any allergies. In the unlikely event that you have a reaction, hospital personnel are able to help you immediately.
You might be asked to change into a gown for the procedure; and to remove jewelry, glasses or metal objects that could interfere with the X-ray.
Women should always inform their physician or technologist if there is any possibility they are pregnant. Caution is taken during pregnancy so as not to expose the baby to radiation.
The Procedure
A technologist specially trained to perform examinations will position you on a table or place you in front of the machine, depending on the type of X-ray being done. A lead apron might be placed over you to protect you from radiation.
You will be asked to hold very still for a few seconds while the X-ray is being taken. The technologist will walk behind a wall or into the next room, and activate the machine. You might be repositioned for another view. A general X-ray is usually completed in five to 10 minutes.
Afterward, you will be asked to wait until the radiologist determines that all the required images have been obtained. The results will be sent to your physician after they are analyzed by the radiologist.
Special care is taken during an X-ray examination to use the lowest radiation dose possible. The radiation dose that a person receives depends upon the part of the body being examined. For example, a spine X-ray is about the same amount of radiation as the average person receives from background radiation over six months. For an X-ray of the extremities, a person receives the same amount of radiation as the average person receives from background radiation in less than a day.