X-RAY EXAMINATION
How x-rays work
A tiny amount of ionising radiation is passed through the body. In the past, this went onto a sheet of special film. Nowadays x-ray examinations are more likely to use a device that will capture transmitted x-rays to create an electronic image.
The calcium in bones blocks the passage of radiation, so healthy bones show up as white or grey. On the other hand, radiation passes easily through air spaces, so healthy lungs appear black.
Benefit x-ray examinations
- Diagnosis of fractures – detection of broken bones is one of the most common uses of this test.
- Diagnosis of dislocations – an x-ray examination can reveal if the bones of a joint are abnormally positioned.
- As a surgical tool – to help the surgeon accurately perform the operation.
- Diagnosis of bone or joint conditions – for example, some types of cancer or arthritis.
- Diagnosis of chest conditions – such as pneumonia, lung cancer, emphysema or heart failure.
- Detection of foreign objects – for example, bullet fragments or swallowed coins.