From the March 2019 issue of HealthCare Business News magazine
“The current data regarding risk of getting cancer from the low radiation doses used in medical imaging is currently unclear. For frame of reference, when we refer to radiation in medical imaging, we are typically talking about less than 100 millisieverts (mSv) of cumulative radiation dose in one’s life. The annual background radiation dose is about 3 mSv per year, and this abdominal CT should result in 1-2 mSv when using proper dose reduction techniques. The available data suggests that the additional risk of a child getting cancer from a CT scan lies anywhere between one in 300 to one in 3000 or possibly much lower when such techniques are used. This tiny additional risk is very difficult to identify upon a background of one in four people dying from cancer naturally.”
The final point in the above paragraph highlights the use of relative risk when discussing radiation. When discussing risk using a statement like “one in 300 chance of getting cancer,” the radiologist must realize that the patient’s caregiver might only be hearing “my child will be that one who gets cancer.” Many hospitals illustrate the relative risk of radiation-induced cancers in creative ways. For example, one children’s hospital created a patient handout describing this as follows: given that the lifetime rate of cancer in all children is about 700 in 3000, if an infant receives a CT scan of the belly, then this rate might increase to 701 in 3000. Other hospitals have created similar handouts with visual representations of the risk of dying from various illnesses in proportionately sized pie charts. Heart disease and cancer (sporadic) combine to occupy more than half the pie, with the risk of dying from cancer from a CT scan corresponding to a very tiny slice. Other institutions compare the risk of radiation-induced cancer to more apparent risks, such as dying from choking or cycling (~0.1 percent), and far less than the chance of getting killed in a car crash. While such topics are clearly morbid, it can be helpful to translate the nebulous risks of radiation into terms that are more concrete and practical for the patient to relate to.
Finally, it is also critically important to consider all your imaging options. In many cases, another imaging modality may be the more appropriate choice, and in certain instances imaging may not be needed at all to direct patient management. While radiation is certainly a concern with pediatric CT exams, more pressing concerns would be confirming the presence or absence of a contrast allergy and if sedation may be required. In this vignette, performing an abdominal ultrasound to look for appendicitis would be preferable to a CT if experienced sonographers are available. Discussing such options with the family and arriving at a mutual decision will build trust and lead to an improved patient experience.
