CT (computerised tomography) scans provide important information that doctors can use to help diagnose medical conditions.
The results of a CT scan can confirm or rule out a suspected diagnosis and they can also sometimes identify unsuspected conditions.
Unlike other imaging techniques, such as X-rays, CT scans can give detailed images of many types of tissue, including bone, lung tissue, soft tissue and blood vessels.
Types of CT scan that can be used to investigate particular areas of the body include:
- head scans - can be used to check for suspected brain tumours and bleeding or swelling of the arteries; head scans are also useful for investigating the brain following a stroke (when the blood supply to part of the brain is cut off)
- abdominal scans - can be used to detect tumours and diagnose conditions that cause internal organs, such as the liver, kidneys, pancreas, intestines or lungs, to become enlarged or inflamed
- vascular scans - can be used to assess conditions that affect the blood flow to different parts of the body
- bone scans - can be used to assess bone injuries and disease, particularly in the spine
CT scans are often used after serious accidents to look for internal injuries, such as tears in the spleen, kidneys or liver.
They are also sometimes used to prepare for further tests and treatments. For example, as CT scans can identify both normal and abnormal tissue, they can be useful when planning radiotherapy treatment.
CT scanning can also act as a guide during a needle biopsy (where a sample of tissue is taken so that it can be examined more closely).
CT scan screening
In recent years, there has been concern that, in some cases, CT scans have been used unnecessarily. Some private medical organisations offer CT screening as a way of detecting conditions in patients who do not have symptoms or any significant risk factors for a disease. This can be both expensive and put you at unnecessary risk.
CT scans are not recommended as a way of giving you peace of mind if you do not have any symptoms. A scan may be recommended if you have symptoms caused by an injury or illness that need to be investigated. However, you should only have a CT scan following a medical referral.
The Department of Health asked a group of experts to investigate the risk of CT scans in healthy people, such as those who decide to pay for a CT scan as part of a private health assessment. In 2007, the Committee on Medical Aspects of Radiation in the Environment (COMARE) produced a report outlining a number of recommendations on the use of CT scans for screening.
The report recommeded that all radiation exposure and equipment used for exposure should be tightly controlled by a number of regulations (both in the NHS and commercially), and that all private sector organisations offering CT screening should provide comprehensive information about a person’s eligibility for screening and the dosage of radiation used.
For full details of all the recommendations, you can read the COMARE report (PDF, 549 kb).
