A CT scan uses X-rays, a form of ionizing radiation, to create detailed images of the inside of the body. This radiation has enough energy to interact with cells and molecules, including DNA, potentially causing damage. When X-rays pass through the body during a CT scan, they can directly break DNA strands or indirectly cause damage by creating reactive molecules called free radicals. These free radicals can attack DNA, proteins, and cell membranes, leading to cellular injury.
DNA damage from CT scan radiation can take several forms: breaks in the DNA strands, mutations, or chromosomal changes. Cells have mechanisms to repair this damage, and often they succeed in fixing it correctly. However, sometimes the repair is faulty, which can lead to mutations. These mutations may accumulate and increase the risk of cancer over time. The risk is stochastic, meaning it can occur at any radiation dose, but higher doses increase the chance of damage and mutation.
Children and young people are more sensitive to radiation because their cells divide more rapidly and they have a longer lifetime ahead during which mutations could develop into cancer. Studies have shown that radiation from medical imaging, including CT scans, is linked to a higher risk of blood cancers like leukemia and lymphoma in children. The risk increases with the cumulative amount of radiation exposure.
Despite these risks, CT scans are valuable diagnostic tools that can save lives by detecting diseases early and guiding treatment. The key is to balance the benefits of the scan against the potential long-term risks and to minimize radiation exposure whenever possible. This is done by following the ALARA principle—keeping radiation “As Low As Reasonably Achievable”—which involves using the lowest effective dose, avoiding unnecessary scans, and employing dose reduction technologies.
To reduce DNA damage from the radiation of CT scans, some research suggests that taking antioxidants before the scan may help. Antioxidants like vitamin C, N-acetylcysteine (NAC), lipoic acid, and beta-carotene can neutralize free radicals generated by radiation, potentially protecting DNA and bone cells from damage. A protocol involving these antioxidants taken several days before a scan has been shown to reduce DNA damage in some studies.
In summary, CT scan radiation can damage DNA by breaking strands and causing mutations through direct and indirect mechanisms involving free radicals. While the body can repair much of this damage, some errors can increase cancer risk, especially with repeated or high-dose exposures. Children are particularly vulnerable. Protective strategies include minimizing unnecessary scans, optimizing scan protocols to reduce dose, and possibly using antioxidant supplements before exposure to mitigate DNA damage. The benefits of CT scans generally outweigh the risks when used appropriately, but awareness and caution are important to safeguard long-term health.