| Radiography (X-ray) - Bone
What is Bone Radiography? Back to Top
Radiography, or as it
is most commonly known, an x-ray, is the oldest and most frequently
used form of medical imaging. Discovered more than a century ago,
x-rays can produce diagnostic images of the human body on film or
digitally on a computer screen.
X-ray imaging is the fastest and easiest way for a physician to view
and assess broken bones, joint or spine injuries. At least two images
(from different angles) are taken and often three images are needed if
the problem is around a joint (knee, elbow or wrist). X-rays also play
a key role in guiding orthopedic surgery and in the treatment of
sports-related injuries. X-ray may uncover more advanced forms of
cancer in bones although early screening for cancer findings requires
other methods.
To this end radiologists have developed alternative imaging methods
that do not rely on radiation, such as ultrasound and magnetic
resonance imaging (MRI). However, because x-ray was the first imaging
modality, many people (and medical imaging professionals) continue to
use the term "radiology" to include all types of imaging. Strictly
speaking, though, radiology refers to the use of x-rays.
What are some common uses of the procedure? Back to Top
Probably
the most common use of bone radiographs is to assist the physician in
identifying and treating fractures. X-ray images of the skull, spine,
joints and extremities are performed every minute of every day in
hospital emergency rooms, sports medicine centers, orthopedic clinics
and physician offices. Images of the injury can show even very fine
hairline fractures or bone chips, while images produced after treatment
ensure that a fracture has been properly aligned and stabilized for
healing. Bone x-rays are essential tools in orthopedic surgery, such as
spinal repair, joint replacements or fracture reductions.
X-ray images can be used to diagnose and monitor the progression of
degenerative diseases such as arthritis. They also play an important
role in the detection and diagnosis of cancer, although usually
computed tomography (CT) or MRI is better at defining the extent and
the nature of a suspected cancer. Severe osteoporosis can be visible on
regular x-rays, but bone density determination for early loss of bone
mineral is usually done on specialized, more sensitive equipment.
How should I prepare for the procedure? Back to Top
There is
no special preparation required for most bone radiographs. You may be
asked to change into a gown before your examination. You will also be
asked to remove jewelry, eyeglasses and any metal objects that could
show up on the images and overlap important findings. Women should
always inform their doctor or x-ray technologist if there is any
possibility that they are pregnant.
What does the x-ray equipment look like? Back to Top
Radiography
equipment consists of a large, flat table with a drawer that holds a
tray into which an x-ray film cassette is placed. Suspended above the
table is the apparatus that holds the x-ray tube that can be moved over
the body to direct the x-ray.
How does the procedure work? Back to Top
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 tissues. Ribs, for
example, are dense and will block much of the radiation and, therefore,
appear white or light gray on the image. Soft tissue such as the liver
or lungs will appear darker because more radiation can pass through it
to expose the film.
The images may be placed on film or may be stored electronically on
PACS (picture archiving and communication systems). Films are usually
stored in a film jacket in the radiology department or in the doctor's
office for approximately seven years (unless the patient is a child,
then until age 21). Images may be digitally acquired or may be
digitized from analog images and can be stored on PACS.
How is the procedure performed? Back to Top
The technologist
positions the patient on the examination table and places a film holder
(cassette) under the table in the area of the body to be imaged.
Sandbags or pillows may help the patient hold the proper position. Then
the technologist steps behind a radiation barrier and asks the patient
to hold very still without breathing for a few seconds. The
radiographic equipment is activated, sending a beam of x-rays through
the body to expose the film. The technologist then repositions the
patient for another view and the process is repeated.
When your x-rays are completed you will be asked to wait until the
technologist checks the images for adequate exposure and motion.
What will I experience during the x-ray procedure? Back to Top
X-ray
imaging itself is painless. Some discomfort may result from lying on
the table, a hard surface that may feel quite cold. Sometimes to get a
clear image of an injury such as a possible fracture, you may be asked
to hold an uncomfortable position for a short time. Any movement could
blur the image and make it necessary to repeat the procedure to get a
useful, clear picture.
Who interprets the results and how do I get them? Back to Top
A
radiologist is a physician experienced in bone x-ray and all other
types of radiology examinations. He or she will analyze the images and
send a signed report to your primary care or referring physician who
will inform you on your test results. New technology also allows for
distribution of diagnostic reports and referral images over the
Internet at many facilities.
What are the benefits vs. risks? Back to Top
Benefits
X-ray imaging is useful to diagnose bone and joint injury and disease, such as fractures, infections, arthritis and cancer.
Because x-ray imaging is fast and easy, it is particularly useful in emergency diagnosis and treatment.
X-ray
equipment is relatively inexpensive and widely available in physician
offices, ambulatory care centers, nursing homes and other locations,
making it convenient for both patients and physicians.
Risks
- X-rays are a type of invisible electromagnetic radiation
and create no sensation when they pass through the body. Modern x-ray
techniques use only a fraction of the x-ray dose that was required in
the early days of radiology.
- Women should always inform their doctor or x-ray technologist if there is any possibility that they are pregnant.
- During
a single x-ray exposure, a patient is exposed to approximately 20
milliroentgens of radiation. To put this into perspective, we are all
exposed to approximately 100 milliroentgens of radiation each year from
sources like the ultraviolet rays of the sun and small traces of
radioactive isotopes, such as uranium found in soil.
- Radiation risks are further minimized by:
- The use of high-speed x-ray film that requires only very small amounts of radiation to produce an optimal image.
- 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 (including mammography systems,
angiographic equipment and CT scanners) that have very tightly
controlled x-ray beams with significant filtration and x-ray dose
control methods. Scatter or stray radiation is minimized and those
parts of a patient’s body not being imaged receive minimal exposure.
What are the limitations of Bone Radiography? Back to Top
While
x-ray images are among the clearest, most detailed views of bone, they
provide little information about the adjacent soft tissues. In the case
of a knee or shoulder injury, for example, an MRI may be more useful in
identifying ligament tears, joint effusions or other problems. Even in
the evaluation of a traumatic injury to the bone that does not cause a
visible crack, MRI can detect a so-called bone "bruise." Other imaging
modalities, such as positron emission tomography (PET), bone scanning
or CT, may be more effective in diagnosing cancer metastases (spread)
to bone or primary bone tumors. MR is especially useful for imaging the
spine because the bones and the spinal cord are evaluated. Ultrasound
(sound waves instead of ionizing radiation) has also been useful in
injuries around joints and in evaluating hips in children for
congenital problems. Back to Top |
