Parents had something new to worry about when a report came out warning about an increased risk of cancer in children who have multiple CT scans.

The study, published in the highly respected medical journal The Lancet in June 2012, showed that children who had two or three CT scans before their fifteenth birthday tripled their risk of getting brain cancer, while those who had between five and ten scans tripled their risk of developing leukaemia.

This has to be put in context however because the overall risk of a child developing these cancers remains small and the need for the CT scan to be carried out is likely to be more important. Despite that reassurance however, parents are still likely to worry.

What are CT scans?

CT stands for computerised tomography and CT scans are also sometimes known as CAT scans. A CT scanner machine generates images from inside the body using several beams from different angles. The pictures provided are far more detailed than a simple x-ray and so can give a far better idea of what is happening in the body. The CT scan can give images of internal organs, bones, blood vessels and tumours.

In children CT scans are often used by doctors to evaluate neurological disorders and injuries to the head, spine or neck.

What are the links between CT scans and cancer?

Radiation can be a problem for our bodies because it can damage genes and lead to an increased chance of developing cancer in the future.

CT scans expose patients to radiation and use more radiation than a standard x-ray. In addition children are more likely than adults to develop a radiation build-up in their bodies. Medical opinion is that children should have a CT scan only if they have a serious condition that is of greater risk.

Different amounts of radiation are used depending on the part of the body being scanned, with the head receiving the smallest dose of radiation.

What are the risks for children?

The Lancet study followed almost 180,000 patients under 22 who received a CT scan in a British hospital over a 17 year period up to 2002. These patients were then tracked until 2008, with 74 of them developing leukaemia and 135 diagnosed with a brain tumour.

Researchers measured the doses of radiation rather than the number of CT scans because how much radiation is delivered depends on the size and age of the patient.

The children who went on to develop cancer were compared to people who received low doses of radiation to the same areas of the body.

Scientists behind the study are keen to stress however that even this higher risk is still small and these remain rare diseases. The risk of childhood leukaemia is around 1 in 2000 so several CT scans would increase that figure to around 1 in 600.

Doctors also want to reassure parents and avoid them potentially refusing permission for a CT scan to be carried out, while at the same time continuing to make sure that the scans are always medically justified.

This guest post has been provided by Nuffield Health who provide jobs in the medical industry such as nursing, doctors & physiotherapy jobs.