When is an X-ray used?
X-ray is useful in many situations. However, an X-ray should only be performed if it is likely to help with diagnosis and improve the treatment or management of your health condition.
The first and most important step to getting an accurate diagnosis is your doctor taking your medical history and performing a physical examination. An X-ray should supplement, not replace, this step.
It’s also important to understand your options and know what each type of imaging involves. The following questions may help you to discuss the options with your health professional, and help you find out more before your X-ray.
Questions to ask your health professional about imaging
- How will the imaging help my condition or injury?
- What does the imaging procedure involve?
- Are there any risks associated with the imaging?
- Are there any other options?
- How much will the imaging cost?
When choosing the type of scan, your doctor should consider your symptoms and the risks, costs and benefits of different scans. Below is a list of situations where an X-ray is usually appropriate. An X-ray may be the only imaging required to diagnose your condition, or the X-ray results may suggest that further tests are required.
Bones and joints
Because bones absorb more radiation than other body parts, X-rays are particularly useful when diagnosing and monitoring bone-related problems such as:
- fractures (broken bones) and dislocations
- problems with teeth, such as tooth decay
- bone infections (osteomyelitis)
- bone cancers (rare).
Many sports injuries will not require an X-ray. For example, ‘rolled ankles’ often result in a sprained joint, not a broken bone, and frequently get better with simple treatment measures (e.g. ice packs, strapping and elevating the ankle). However, if the doctor believes imaging is required after a physical examination of a bone or joint-related injury, X-ray is usually the first choice. More sophisticated scans, such as CT or MRI, are usually only ordered if the X-ray and doctor’s examination suggest further investigations are necessary.
Radiation passes easily through air spaces, so healthy lungs will generally appear dark grey. Your doctor may order a chest X-ray to investigate symptoms such as:
- shortness of breath
- a bad or persistent cough
- chest pain.
A chest X-ray can help identify health problems such as:
- lung conditions, such as pneumonia, lung cancer and chronic obstructive pulmonary disease (COPD — one form of which is sometimes known as emphysema)
- broken ribs
- (less commonly) heart conditions, such as an enlarged heart.
X-rays using contrast media
During a coronary angiogram, contrast media is injected using a small tube (called a catheter) inserted into an artery in the groin (usually) or arm and guided to the heart using X-ray imaging. After the contrast dye is injected, the blood vessels become visible on X-rays. The X-ray images that are produced (angiograms) are able to highlight whether a blood vessel in the heart is blocked.
Barium is another type of contrast medium. In a barium swallow, you are given a solution to drink, after which a series of X-rays will be taken. This can be used to help diagnose the cause of swallowing problems (dysphagia). Similarly, a barium enema can be used to help diagnose bowel problems. However, barium swallows and barium enemas are less commonly used these days — endoscopy (for stomach and oesophagus problems) and colonoscopy (for bowel and rectum problems) are generally preferred for investigating gastrointestinal complaints, including dysphagia.