By Isabelle Thierry-Chef, ISGlobal researcher and principal investigator of the HARMONIC project.

Isabelle Thierry Chef

There are numerous strategies to reduce radiation dose that children receive from diagnostic imaging tests. The key is to ensure that the benefits of the procedure largely outweigh the risk involved.

The use of radiation in pediatric imaging is saving lives; its clinical value in the diagnosis of pediatric diseases and injuries is unquestionable and advances in radiotherapy have resulted in major improvements regarding long-term survival of paediatric patients. However, these techniques have become the largest source of exposure to ionizing radiation (that radiation with sufficient energy to break chemical bonds and cause damage to cells), to which humans are exposed, especially computed tomography (CT scanning). Since radiation exposure is potentially associated with increased risk of cancer and non-cancer diseasesevaluation of associated long-term health effects is essential, even more in the paediatric population since children have a long-life expectancy and they are more sensitive for the development of some cancers.

Radiation health risk

Radiation risk to human health has been the subject of much research. Recently, the first results of the large EPI-CT study, including about 1 million young patients from 9 European countries receiving CT scanning, added evidence on a slightly increased risk of brain cancer following exposure to doses in the low-dose range which strengthen the results from previous cohort studies investigating cancer effects of exposure to ionising radiation in childhood and adolescence in CT scanning.

Although radiation dose for a single procedure might be low, pediatric patients often receive repeated examinations over time, which could result in relatively high cumulative doses, depending on their health conditions. To ensure that the benefits for patients far outweigh the radiation risks, these procedures should be appropriately prescribed and performed.

Steps to reduce the radiation dose children receive

It is often possible to take steps to reduce the radiation dose children receive without compromising image quality and interpretationThe radiation dose can be adjusted based on the procedure and the detail of the images required for making the diagnosis, considering the size of the child. To achieve an acceptable image in younger children, lower levels of radiation are required.

Radiation protection is based on two main principles: justification and optimization.

The principle of justification

The principle of justification applies at three levels:

  1. The appropriate use of radiation in the medical field is accepted as it does more good than harm.
  2. A specific procedure is justified for a group of patients showing relevant symptoms or for a group of people at risk of developing a disease that can be detected and treated.
  3. The application of a specific procedure to an individual patient is justified if that application is considered to do more good than harm to the patient.

When appropriate and available, it is preferable to use imaging methods that do not use ionizing radiation, for example, ultrasound (ultrasound) or MRI (radio frequency and electromagnetic waves), particularly in children.

The most effective way to reduce the radiation dose associated with pediatric radiodiagnosis is to reduce the number of procedures or, preferably, to dispense with those that are unnecessary or inappropriate.

The duplication of diagnostic imaging tests already performed in other healthcare facilities represents a considerable percentage of these unnecessary tests. In order to avoid this repetition, sufficient information (including images and medical reports) with sufficient detail must be previously collected and made available to healthcare professionals.

The referring physician should ask a number of questions when considering imaging procedures:

  • Has it been done in the patient before?
  • Do I need it? – Will the result influence patient care or strengthen confidence in the diagnosis?
  • Do I need it now?
  • Is it the best clinical test? – Are there other alternatives?


The principle of optimization

When decision to perform the relevant imaging procedure has been taken, the general principles of optimization should be considered. The objective is to ensure the lowest dose of radiation necessary to provide an image from which an accurate diagnosis can be obtained and appropriate to the patient’s weight and age.

For this purpose, a series of tools are available that provide an indication of the expected radiation dose that a patient receives according to his or her size and the procedure performed.

In conclusion, the benefits of using ionizing radiation for the diagnosis or treatment of pediatric diseases far outweigh the associated risks. But we know that the risk is not zero, so it is necessary to justify the need for such tests and to optimize the dose to achieve the necessary diagnostic quality with the lowest possible dose.

This post was first published in the Health is Global blog.