Radiography (X-ray) - Chest
What is Chest Radiography?
Chest x-ray is the most commonly performed diagnostic x-ray examination.
Approximately half of all x-rays obtained in medical institutions are chest
x-rays. A chest x-ray is usually done for the evaluation of lungs, heart
and chest wall. Pneumonia, heart failure, emphysema, lung cancer and other
medical conditions can be diagnosed or suspected on a chest x-ray. Traditionally,
chest x-rays have been taken prior to employment, prior to surgery or during
immigration. The use of "routine" chest x-rays is being reevaluated
because there is a lack of evidence for their usefulness, and many insurance
companies no longer pay for these "routine" x-rays obtained in
absence of specific signs, symptoms or medical conditions.
< - top - >
What are some common uses of the procedure?
Sample image: Chest x-ray. Frontal view of a male patient.Chest x-ray is
typically performed as the first imaging test for symptoms of shortness
of breath, a bad or persistent cough, chest pain, chest injury or fever.
Individuals with known or suspected medical conditions such as congestive
heart failure or cancer may have chest x-rays to follow their response
to treatment, or to determine changes that would require a change in their
medical management.
< - top - >
How should I prepare for the procedure?
This procedure requires no special preparation. Women should always inform
their doctor or x-ray technologist if there is any possibility that they
are pregnant.
< - top - >
What does the x-ray equipment look like?
The most common radiography equipment used for chest x-rays consists of
a box-like apparatus containing the recording material—such as film
or a digital recording plate against which the individual places his/her
chest—and the apparatus containing the x-ray tube, usually positioned
about six feet away. In some instances, the radiography equipment consists
of a large, flat table with a drawer that holds an x-ray film cassette
or a digital recording plate. With this arrangement, the x-ray tube is
suspended above the table.
< - top - >
How does the procedure work?
Radiography involves exposing a part of the body to a small dose of radiation
to produce an image of the internal organs. When x-rays penetrate the body,
they are absorbed in varying amounts by different parts of the anatomy.
The ribs and spine, for example, absorb much of the radiation and appear
white or light gray on the image. Lung tissue absorbs little radiation
and appears dark on the image. Depending upon the type of image-recording
medium, chest x-rays can be maintained as hard copy film for filing or,
more commonly, as filmless digital images that are archived electronically.
Digital images can also be transferred for storage onto CD-ROM. Stored
images may be used to compare with later images if illness develops. Indeed,
historical comparison films are often very important in the decision process
as to whether a finding is clinically important or not.
< - top - >
How is the procedure performed?
Radiography equipmentPatients must remove their clothing, including undergarments
that may contain metal. Most medical centers will give the patient a loose-fitting
gown to wear. Patients will also be asked to remove all metallic jewelry
that may interfere with the x-rays. Normally, a frontal or posteroanterior
view is obtained, in which the patient stands with the chest pressed to
the photographic plate, with hands on hips and elbows pushed in front in
a somewhat exaggerated position. The technologist will ask the patient
to be still and to take a deep breath and hold it. Breath-holding after
a deep breath reduces the possibility of a blurred image and also enhances
the quality of the x-ray image, since abnormalities in air-filled lungs
are easier to see than in deflated lungs. Next, the technologist walks
into a cubicle or small room to activate the radiographic equipment, which
sends a beam of x-rays from the x-ray source behind the patient, through
the patient's chest, to the recording medium (film or digital cassette).
Some equipment is designed to accommodate patients who cannot stand for
chest x-rays.
The technologist may need to take additional views to properly see all parts
of the chest or may take a side view, or lateral view, of the chest. For
a lateral view, the patient stands sideways to the photographic plate with
arms elevated, and the process is repeated. Views from other angles may
be obtained if the radiologist needs to evaluate additional areas of the
chest. Finally, a chest x-ray may be repeated within hours, days or months
to evaluate for any changes. These repeated, sequential examinations are
called serial chest x-rays.
When the chest x-rays are completed you will be asked to wait until the
technologist checks the images for motion and makes sure that the entire
chest is included. Ultimately, a radiologist will interpret the chest x-ray
images using a lighted view box to review films or a computer and monitor
to review digital images.
< - top - >
What will I experience during the x-ray procedure?
This is a painless procedure. The primary discomfort may come from the coldness
of the recording plate. Individuals with arthritis or injuries to the chest
wall, shoulders or arms may have discomfort trying to maintain position
for the chest x-ray. In these circumstances, the technologist will assist
you in finding a position that still ensures diagnostic image quality.
< - top - >
Who interprets the results and how do I get them?
Sample image: Chest x-ray. Side view of the chest.A radiologist, who is
a physician specifically trained to supervise and interpret radiology examinations,
will analyze the images and send a signed report with his or her interpretation
to your primary care physician or other health care provider, who will
inform you of your test results. New communications technology also allows
for confidential distribution of diagnostic reports and digital images
over the Internet at many facilities.
< - top - >
What are the benefits vs. risks?
Benefits
- A physician may recommend a chest x-ray for a patient with shortness
of breath, a bad or persistent cough, chest pain or a chest injury.
In the instances of pneumonia, the site of pneumonia will appear white
on the image.
- A chest x-ray may also show advanced emphysema as well as other diffuse
lung conditions, such as pulmonary fibrosis.
- Lung cancers and tumors that spread to the lung may be visible on chest
x-ray. However, lesions that are small or superimposed on normal
structures may not always be visible.
- Heart irregularities, such as fluid around the heart (pericardial effusion),
an enlarged heart, or abnormal heart anatomy or congestive heart
failure may also be visible on a chest x-ray.
- Pleural effusions (fluid around the lungs) on one or both sides can
be detected. Usually the cause of such fluid may be deduced from clinical
data or other findings on the chest x-ray but it may be necessary
to sample the fluid to determine its cause.
Risks
- X-rays are a type of electromagnetic radiation, are invisible and create
no sensation when they pass through the body. The chest x-ray
is one of the lowest radiation exposure medical examinations performed
today.
- Special care is taken during chest x-ray examinations to ensure maximum
safety for the patient by paying attention to correct x-ray beam
energies. Shielding the abdomen and pelvis with a lead apron helps reduce
unnecessary radiation to the abdomen and pelvis. Women should always inform
their doctor or x-ray technologist if there is any possibility that they
are pregnant.
- The effective radiation dose from this procedure is about 0.1 mSv, which
is about the same as the average person receives from background
radiation in 10 days.
Radiation risks are further minimized by:
- Technique standards established by national and international guidelines
that have been designed and are continually reviewed by national
and international radiology protection councils.
- Modern, state-of-the-art x-ray systems that have tightly controlled
x-ray beams with significant x-ray beam filtration and dose control methods.
Thus, stray or scatter radiation is minimized and those parts of
a patient's body not being imaged receive minimal exposure.
< - top - >
What are the limitations of Chest Radiography?
The chest x-ray is a very useful examination, but has limitations. Some
conditions of the chest will not show up on the image. Therefore, a normal
chest x-ray does not necessarily rule out all problems in the chest. For
example, patients with asthma exacerbations can have a normal chest x-ray.
There are some cancers that are too small or are difficult to visualize
and may not be identified. Blood clots to the lungs (pulmonary embolism)
cannot be seen on chest x-rays and require additional study.
A chest CT may be requested to further clarify a finding seen on the chest
x-ray or to look for an abnormality not visible on a chest x-ray in order
to answer the clinical problem. The degree of involvement of the lung,
as well as the distribution of disease, and anatomic location may be better
evaluated with chest CT, helping aid the diagnosis. Some diseases, such
as chronic lung disease, are frequently evaluated with HRCT (high-resolution
CT).
The chest x-ray and the physical examination should be correlated. The information
each procedure provides can give the physician a clearer understanding
of the patient's health.
< - top - >
