Risk of Tumors or Cancer from Head CT Scans

Understanding Radiation Exposure from Head CT

A typical head CT scan exposes patients to approximately 2-4 mSv of radiation, which is equivalent to about 100-200 chest x-rays, according to the American Academy of Otolaryngology-Head and Neck Surgery 1
The International Commission on Radiological Protection has reported that CT doses can approach or exceed levels shown to result in increased cancer risk, as stated by the American College of Radiology 2
X-rays have been officially classified as a "carcinogen" by multiple international health organizations, including the World Health Organization's International Agency for Research on Cancer, as reported by the American College of Radiology 2

Children are at higher risk than adults because they have more actively dividing cells, according to the American Academy of Otolaryngology-Head and Neck Surgery 3
Children are at higher risk than adults because they have a longer life span during which radiation-induced tumors can develop, as stated by the American Academy of Otolaryngology-Head and Neck Surgery 3 and also reported by the same society 1

Approximately 0.4% of all cancers in the United States may be attributable to radiation from CT studies, according to the American Academy of Otolaryngology-Head and Neck Surgery 1

For children with mild traumatic brain injury, clinical decision rules like the PECARN rules can help identify children at very low risk for clinically important brain injury who can safely avoid CT scans, as recommended by the American Academy of Pediatrics 4

Radiation doses from CT scans should be kept as low as reasonably achievable (ALARA principle), as recommended by the American Academy of Pediatrics 4
Technological advances in CT scanning have helped reduce radiation doses while maintaining diagnostic quality, according to the American Academy of Otolaryngology-Head and Neck Surgery 1
Standardized study descriptions and patient size descriptors can help track and minimize radiation exposure, as reported by the Radiological Society of North America 5

Risk communication about CT scans is often inconsistent, with most risks (65%) communicated using text rather than visual formats, as found by the American College of Radiology 6
Visual formats may enhance comprehension of risk information without bias, according to the American College of Radiology 6
Patient decision aids can assist in the process of considering and weighing risks, but there is no consistent manner of communicating radiation risk to patients, as stated by the American College of Radiology 6

The World Health Organization has classified ionizing radiation from CT scans as a carcinogen, and it is essential to discuss both risks and benefits with parents 7
For almost all patients, the adverse health consequences of refusing a needed medical procedure far outweigh any potential radiation-associated risks 8

The American College of Radiology recommends using clear, balanced language and visual formats to enhance comprehension without bias when discussing radiation risks with parents 9, 10
It is crucial to avoid using effective dose calculations and the Linear No-Threshold (LNT) model to predict population-level cancer deaths, as these predictions are highly suspect and can create substantial public anxiety 8

The American College of Radiology suggests explaining that cancer risk estimates come primarily from studies of atomic bomb survivors exposed to much higher doses, and extrapolating to lower CT doses involves uncertainty 8, 11
Radiation-induced cancers typically do not occur until 1-2 decades or longer after exposure, and it is virtually impossible to detect them at doses less than 100 mSv in a population 7, 8

The American College of Radiology advises against minimizing or dismissing parental concerns, as the risk is small but real, and parents have a right to informed decision-making 12, 8
It is essential to avoid creating excessive fear and using inconsistent risk communication, as variability in how risks are presented can affect decision-making, especially among parents with lower health literacy 9, 10, 8