Introduction: Computer Tomography (CT) scans can deliver a relatively high radiation dose to the patient, therefore radiation protection for this modality is paramount. The present study determined the frequency of no abnormality detected (NAD) brain CT scans and probability of cancer induction in different age groups and genders. Methods: In this study, brain CT reports were used to identify any findings as abnormality detected (AD) and others as NAD. Then probability of future leukemia and brain cancer was estimated for different age and gender groups. Results: On average, in 65% of the cases the results were NAD (56% and 76% among males and females, respectively). Among children, 79% of the reports were NAD. The total number of projected brain cancers was 1.8 and 1.3 for males and females, respectively. The number of projected leukemia cases was 0.75 and 0.7 for males and females, respectively. For pediatric patients, brain CT scans can lead to leukemia cases about 4.5 times more often than adults. Conclusion: Brain CT scans can lead to additional cases of brain cancer and leukemia. A significant fraction of brain CTs were NAD (non-pathologic) and could practically be replaced by other radiation-free imaging modalities, especially in pediatric and young patients.
