Imaging choices for children

Be aware of radiation risks

One of the factors to consider when choosing the type of imaging is the amount of radiation exposure to a child.

High-energy, radioactive particles or rays (known as ionising radiation) are used in plain X-ray, CT scans and nuclear medicine imaging.

CT scans use higher amounts of radiation than plain X-ray or nuclear medicine imaging, particularly when examining the head, chest or abdomen. MRI and ultrasound use no ionising radiation.

The amount of radiation in an X-ray or CT scan is relatively small considering our constant exposure to 'background' radiation in the environment throughout our life. But exposure can differ with each imaging type, each part of the body and the total area exposed. Because children's bodies are still developing, radiation risks are greater in children than in adults.

Health professionals, technicians and the equipment they use aim to minimise the radiation exposure from any one imaging test.

Your child may need an X-ray first

Plain X-rays are often the first imaging type used when investigating a range of conditions, including certain traumatic joint and bone injuries. Depending on the results, a doctor may then request an additional type of imaging for your child, such as a CT scan or MRI.

CT could be the appropriate choice

CT is often the most appropriate imaging choice for investigating chest and abdomen problems — and may provide essential information that other types of imaging could miss.

A CT scan can be particularly useful for various situations managed in hospital emergency departments. However, it does involve higher doses of radiation than other types of imaging. Read more about the types of imaging and their advantages and disadvantages.

MRI might be the right option

In some cases, MRI can provide similar diagnostic information to CT. MRI does not use ionising radiation and so is often preferred to a CT scan for anyone under the age of 20.

While MRI avoids the risks associated with radiation, like other types of imaging, it should only be used after weighing up the risks and benefits. There may be situations where a CT scan will still be preferable because of the condition suspected and the type of image required.

MRI does have some disadvantages. For example, your child may need to be sedated or undergo anaesthesia during an MRI, as the procedure can be lengthy and noisy and your child must remain motionless throughout. It can also cause some adults and children to feel anxious or claustrophobic.

Find out ways to help your child during imaging.

Ultrasound is another option

Ultrasound is another imaging type that uses no ionising radiation. It can be used to examine various parts of the body including the abdomen, kidneys, muscles, bones and joints, testes, and the thyroid gland.

In some cases, ultrasound may be used instead of CT, such as when investigating possible appendicitis. But as with MRI, ultrasounds also have disadvantages that need consideration.

For example, the quality and interpretation of an image is highly dependent on the skill of the person doing the ultrasound. Sound waves used in ultrasound can't see through calcified parts of the body such as bones, which can also affect image quality. A CT scan may be more accurate in certain situations.

New Medicare support for MRI

People under the age of 16 can now receive a Medicare rebate for some MRI procedures following GP referral. Previously these were only subsidised through Medicare after specialist referral.

For example, a GP can refer a child for an MRI of the head that is eligible for a Medicare rebate but only for certain reasons, such as for investigating unexplained headache where a serious cause needs to be excluded.

Some MRI procedures of the spine, knee, hip, elbow and wrist requested by a GP are also eligible for a Medicare rebate but require an X-ray first.