Chest X-Ray Test
Facts and Definition of Chest X-Ray
- A chest X-ray test is a very common, non-invasive radiology test that produces an image of the chest and the internal organs.
- To produce a chest X-ray test, the chest is briefly exposed to radiation from an X-ray machine and an image is produced on a film or into a digital computer.
- Chest X-ray is also referred to as a chest radiograph, chest roentgenogram, or CXR.
- Depending on its density, each organ within the chest cavity absorbs varying degrees of radiation, producing different shadows on the film.
- Chest X-ray images are black and white with only the brightness or darkness defining the various structures. For example, bones of the chest wall (ribs and vertebrae) may absorb more of the radiation and thus, appear whiter on the film.
- On the other hand, the lung tissue, which is mostly composed of air, will allow most of the radiation to pass through, developing the film to a darker appearance. The heart and the aorta will appear whitish, but usually less bright than the bones, which are more denser.
- Chest X-rays tests are ordered by physicians for a variety of reasons. Many clinical conditions can be evaluated by this simple radiology test. Some of the common conditions detected on a chest X-ray include:
- In general, a chest X-ray test is a simple, quick, inexpensive, and relatively harmless procedure with minimal risk of radiation. It is also widely available.
Chest X-ray Test Procedure
To prepare for a chest X-ray, the patient is typically instructed to wear a gown and remove all metal containing objects around the upper body (necklaces, zippers, bras, buttons, jewelry, eyeglasses, etc.) as these will interfere with the visualization of the tissues. No other specific preparation, such as fasting, is necessary for a routine chest X-ray.
The patient is then asked by the technician to stand in front of a surface adjacent to the film that records the images. The front of the chest is closest to the surface. Another part of the machine that releases the radiation is then placed about 6 feet away, behind the patient. When the positioning is appropriate (normal standing position with arms on the sides), the technician may advise the patient to take a deep breath and hold it and then takes the image by activating the device (similar to taking a regular photograph). The image is then captured on the film within a few seconds. The film can be developed within a few minutes to be reviewed by the doctor.
Usually one image is done from back to front (referred to as posterior-anterior, or "PA" view) and, as described above, a second image using a sideways view from side-to-side (lateral) can be done as well.
In situations where someone is unable to stand (too weak, disabled, or hospitalized), the image can be taken while laying down with the recording surface placed behind the back. Because the image is taken from the front to back in this scenario, it is called an anterior-posterior (AP) view. A lateral film is generally not possible in these situations. This method can also be called a portable chest X-ray because the X-ray machine is wheeled in to the patient in order to take the X-ray. Other chest images from different positions are sometimes ordered by the doctor for special situations.
How to Prepare for Chest X-ray Test
As noted above, usually a gown is worn and metal containing materials are removed from the body before an X-ray is taken. Pregnant women need to notify the doctor and the technician as some or all images may not be taken in order to avoid unnecessary X-ray radiation exposure to the fetus. Precautions, such as, protective lead covers may be placed on the abdomen to avoid radiation to the fetus when an X-ray is absolutely necessary.
Medically Reviewed by a Doctor on 8/4/2017
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