X-ray - When X-ray is used

Bone is a very hard and dense tissue that shows up clearly on X-rays. X-rays are therefore very useful for diagnosing bone-related problems.

For example, X-rays can be used to help identify:

• fractures and breaks
• problems with teeth, such as loosening of the teeth, root erosion and dental abscess, which can all be indirect signs of tooth decay
• thinning and weakening of the bones (osteoporosis) 
• bone infection (osteomyelitis)
• an abnormal curvature of the spine (scoliosis)
• bone tumours, which can either be benign (non-cancerous) or malignant (cancerous) 

X-rays are also sometimes used during investigative or therapeutic procedures to help the surgeon guide equipment to the area being examined or treated.

For example, X-rays are often used during a coronary angioplasty, where a catheter (a long, thin, flexible tube) is inserted into a blood vessel either in your groin or arm.

X-rays are used to guide the tip of the catheter to your heart or the arteries that supply your heart. A special fluid called contrast medium, which shows up clearly on X-rays, is injected through the catheter. The images produced, known as angiograms, are able to highlight whether a blood vessel is blocked.

Chest examination

Major organs and blood vessels don't show up as clearly on X-rays as bones, but they are visible. A chest X-ray is therefore a good way of identifying changes or abnormalities in your heart, lungs and major arteries.

In particular, chest X-rays can help diagnose:

• heart conditions – such as heart failure, congenital heart disease and pericarditis (inflammation of the heart lining)
• lung conditions – such as pneumonia, lung cancer and chronic obstructive pulmonary disease (COPD)

Contrast medium

Contrast medium is liquid that contains dye. It's sometimes swallowed or injected before an X-ray is taken and shows up clearly in white, helping to distinguish between different structures in the body.

Contrast medium is usually harmless and passes out of the body in your urine or faeces. However, in rare cases it can cause an allergic reaction. Make sure you tell the radiologist if you've had an allergic reaction to iodine or contrast medium in the past, or if you have any other allergies.

Types of X-ray

There are various ways that X-rays can be used to investigate different parts of the body. These are described below.

Barium swallow

Barium is a type of contrast medium that you may be given in a solution to drink. After the barium has passed into your upper digestive system, a series of X-rays will be taken.

A barium swallow can be used to diagnose problems with the upper digestive system, such as swallowing problems (dysphagia) and persistent symptoms of abdominal pain.

Barium enema

A barium enema involves barium solution being pumped through your anus (back passage) and into your bowel.

Barium enemas can be used to diagnose bowel problems, such as persistent constipation and blood in your faeces (stools).

Angiography

Angiography is a type of X-ray used to examine blood vessels. The images created during angiography are called angiograms.

As blood vessels don't show up clearly on ordinary X-rays, contrast medium is injected into the area being examined. The dye highlights the blood vessels as it moves through them, showing up in white on the angiogram.

Studying the movement of the dye through a blood vessel can often highlight problems, such as blockages.

Less commonly, angiographies are also carried out using magnetic resonance imaging (MRI) and computerised tomography (CT) techniques.

Intravenous urogram (IVU)

During an intravenous urogram (IVU), contrast medium is injected into your veins.

Iodine solution is usually used, which moves into your kidneys and bladder. X-rays of your kidneys and bladder will then be taken.

IVU is often used to diagnose problems with the urinary system.