Bone X-Rays

Greenstick fracture through the lower third of the radius (forearm). There is a further undisplaced fracture through the upper radial shaft without deformity.

X-ray imaging is the fastest and easiest way for a physician to view and assess broken bones, cracked skull and an injured spine.  Images of the injury can show very fine hairline fractures or chips, while images produced after treatment ensure a fracture has been properly aligned and stabilised for healing.

X-rays play a key role in orthopaedic surgery such as spinal repair, joint replacements or fracture reductions.  Bone x-rays are an essential tool in the treatment of many sports injuries. X-rays can be useful in detecting advanced forms of bone cancer, although very early detection of bone cancer requires other methods such as Computerised Tomography (CT) or Magnetic Resonance Imaging (MRI).

X-rays can be used to diagnose and monitor the progression of degenerative diseases such as arthritis.  Severe osteoporosis may be visible on x-rays, but bone densitometry is used to detect early loss of bone density and is done on special equipment.

Chest X-rays

Chest x-ray of 62 year old male showing appearances within normal limits

A chest x-ray is usually done for the evaluation of heart, lungs and surrounding anatomy.  Pneumonia, heart failure, pleurisy and lung cancer can be diagnosed on a chest x-ray, along with other less common conditions.

Chest x-ray might be used to evaluate shortness of breath, a bad or persistent cough, chest pain, a chest injury and fever.  It is helpful to confirm or rule out the presence of pneumonia.  A chest x-ray may also show the size, location and amount of tissue damaged by a blood clot in the lung (pulmonary embolism) or the severity of bronchitis or emphysema.  Heart irregularities such as fluid around the heart (pericardial effusion), an enlarged heart, or abnormal heart anatomy may also be revealed.

Preparation for an X-ray Examination

There is no special preparation for general radiography.  You may be required to change into a gown for your examination, and to remove jewellery, dentures, eyeglasses and any metal objects that could obscure the x-ray images.  Women should always inform their doctor or the x-ray technologist if there is any possibility that they are pregnant.

X-ray Equipment

Radiography equipment consists of a large flat table with a drawer that holds an x-ray image recording plate.  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.

PHOTO: Positioning patient for shoulder x-ray.

How X-Rays Work

Radiography involves exposing a part of the body to a small dose of radiation to produce an image of the bones or internal organs.  When x-rays penetrate the body they are absorbed in varying amounts by different parts of the anatomy.  Ribs, for example will absorb much of the radiation, and appear white or light grey on the image.  Soft tissue such as the lungs or liver will appear darker because they absorb less radiation.

Digitak x-ray images are produced, which the Radiologist, who is a doctor specialising in radiology examinations, then analyses and sends a signed report with his or her interpretation of the findings to the patients doctor.

During a procedure, a patient is exposed to approximately 20 milliroentgens of radiation.  This compares with the 100 milliroentgens of radiation we are exposed to each year from sources such as the suns ultraviolet rays, television and traces of uranium found in the soil.

Modern state-of-the-art x-ray systems have very tightly controlled x-ray beams with significant filtration and x-ray dose control methods.  Thus, scatter or stray radiation is minimised and those parts of a patient’s body not being imaged receive minimal exposure.  Radiation risk is further minimised by the use of high-speed film that requires only very small amounts to radiation to produce an image.

The X-ray Procedure

The Technologist positions the patient on the examination table, places a flat cassette under the table in the area to be imaged.  For a chest x-ray the patient will normally stand with the chest pressed to the photographic plate.  The technologist will ask the patient to be still.  The radiographic equipment is activated, sending a beam of x-rays through the body tto a special digital image recording plate within the cassette.  In the case of a chest x-ray, the patient will be asked to take a deep breath and hold it.  This not only reduces the possibility of a blurred image but enhances the quality of the image, since air-filled lungs are easier to see on x-ray than deflated lungs.  These processes may be repeated if further views are required.

Once the x-rays are completed you will be asked to wait while the Radiologist examines the images to determine if any more are needed.

In most cases, x-ray imaging is painless.  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 few seconds.  Any movement could blur the image and make it necessary to repeat the procedure.

The Limitations of Radiography

While x-ray images are among the clearest, most detailed views of bone tissue, they may not provide adequate information about soft tissues.  In the case of a knee or shoulder injury, for example, an ultrasound or MRI may be more useful in identifying small ligament or tendon tears or other problems.  Bone scans or CT may be more effective in diagnosing small tumours in the bone.

Some diseases of the lung do not show up on chest x-ray.  A normal chest x-ray does not necessarily rule out pulmonary problems.  Patients with asthma, for example, can have normal chest x-rays.