A gentleman by the name of William Roentgen discovered x-rays in 1895, which by the way was the same year that D.D. Palmer discovered Chiropractic. Roentgen was experimenting in his laboratory and by happenstance placed his hand in front of a plate and he saw his hand and its movements. Thus the first fluoroscopy was brought into the world. It was shortly thereafter that the first imaging plates were available on the market.

Radiography, known to most people as x-ray, is the oldest and most frequently used form of medical imaging. For nearly a century, diagnostic images have been created by passing small, highly controlled amounts of radiation through the human body, capturing the resulting shadows and reflections on a photographic plate.

X-ray imaging is the fastest and easiest way for a physician to view and assess broken bones, cracked skull and injured backbone. At least two films are taken of a bone, and often three films if the problem is around a joint (knee, elbow, or wrist). X-rays also play a key role in orthopedic surgery and the treatment of sports injuries. X-ray is useful in detecting more advanced forms of cancer in bones. Very early cancer findings require other methods.

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 (a form of application or employment of a therapeutic agent or regimen), 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.

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 chips, while images produced after treatment ensure that a fracture has been properly aligned and stabilized for healing. Bone x-rays are an essential tool 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. On regular x-rays severe osteoporosis is visible, but bone density determination detects early loss of bone density. Bone density determination is usually done on special equipment.

There is no special preparation required for most bone radiographs. Once you arrive, 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 obscure the images, since those show up on x-rays and may block the bones. Women should always inform their doctor or x-ray technologist if there is any possibility that they are pregnant.

Radiography equipment consists of a large, flat table with a drawer that holds an x-ray film cassette into which a film is placed. Suspended above the table, is an apparatus that holds the x-ray tube that can be moved over the body to direct the x-ray.

The image to the left is an example of the radiography equipment that may be used.
 

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 part of the anatomy. Ribs, for example, will absorb 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 it absorbs less radiation. Broken bones or malignancies in the bone can usually be detected with radiography.

The exposed film is either placed in a developing machine, producing images much like the negatives from a 35 mm camera, or images are digitally stored on computer.

The technologist positions the patient on the examination table, places a flat 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 goes to a small adjacent room 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. Usually, a bone exam takes less than 15 minutes.

When the x-rays are completed you will be asked to wait until the technologist and radiologist examine the images to determine if more are needed.
 

In most cases, x-ray imaging is painless and the only discomfort results from the coldness of the plate. 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?
A radiologist, who is a physician experienced in bone x-ray and other radiology examinations, will analyze the images and send a signed report with his or her interpretation to the patient’s personal physician. The personal physician's office will inform the patient on how to obtain their results. New technology also allows for distribution of diagnostic reports and referral images over the Internet at some facilities.

Benefits

• X-ray imaging is useful to diagnose bone injury and disease, such as fractures, bone infections, arthritis, and cancer.

• Because x-ray imaging is so 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. So examinations are usually 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 required in the early days of radiology.

• Special care is taken during x-ray examinations to ensure maximum safety for the patient by shielding the abdomen and pelvis with a lead apron, with the exception of those examinations in which the abdomen and pelvis are being imaged. Women should always inform their doctor or x-ray technologist if there is any possibility that they are pregnant.

• During a procedure, a patient is exposed to approximately 20 milliroentgens (one-thousandth of a roentgen (the international unit of exposure dose for x-rays or gamma rays) of radiation. This compares with the 100 milliroentgens of radiation we are all exposed to each year from sources such as the ultraviolet rays of the sun and the traces of uranium found in the 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, labs, and CT scanners) that have very tightly controlled x-ray beams with significant filtration and x-ray dose control methods. Thus, scatter or stray radiation is minimized and those parts of a patient’s body not being imaged receive minimal exposure.

While x-ray images are among the clearest, most detailed views of bone tissue, they may not provide equally revealing information about involved soft tissues. In the case of a knee or shoulder injury, for example, an MRI may be more useful in identifying small ligament tears or other problems. Other imaging modalities, such as bone scans or CT, may be more effective in diagnosing small tumors in the bone.