Pediatric imaging, especially using CT (computed tomography) scans, is a critical tool in diagnosing and managing many childhood illnesses and injuries. However, one of the main concerns with CT scans in children is the amount of radiation they receive during the procedure. Understanding how much radiation is involved, why it matters, and how it is managed can help parents and caregivers make informed decisions about their child’s healthcare.
CT scans use X-rays to create detailed images of the inside of the body. Unlike a regular X-ray, which produces a single flat image, a CT scan takes multiple cross-sectional images that can be combined to form a 3D picture. This allows doctors to see organs, bones, blood vessels, and tissues with much greater clarity. But because CT scans use ionizing radiation, which can damage cells and DNA, there is a potential risk associated with exposure, especially in children who are more sensitive to radiation than adults.
The amount of radiation a child receives from a CT scan is measured in millisieverts (mSv), which quantifies the effective dose of radiation considering the type of radiation and the sensitivity of the tissues exposed. For pediatric CT scans, the radiation dose varies widely depending on the type of scan, the area of the body being imaged, the size and age of the child, and the technology used by the CT machine.
For example, in pediatric sinus imaging, recent advances have allowed the use of low-dose CT protocols that deliver radiation doses comparable to standard X-rays, around 0.05 mSv. This is a significant reduction from older CT protocols that might have delivered doses closer to 0.1 mSv or higher. These low-dose CT scans use optimized settings such as lower tube voltage (around 80 kV), reduced tube current (mAs), faster scan rotation times, and higher pitch factors to minimize radiation while maintaining diagnostic image quality.
In other types of pediatric CT scans, such as cardiac CT, radiation doses can vary more. Newer technologies like photon-counting detector CT (PCDCT) can provide detailed images but may sometimes result in higher radiation doses compared to traditional energy-integrating detector CT (EIDCT), especially in infants. The balance between image quality and radiation dose is carefully managed by radiologists and technologists to ensure the lowest dose possible for the clinical question at hand.
To put these doses into perspective, natural background radiation that everyone is exposed to from the environment averages about 3 mSv per year. A typical pediatric CT scan might range from about 0.05 mSv for a low-dose sinus CT to a few millisieverts for more complex scans like chest or abdominal CTs. For example, a pediatric chest CT might deliver around 1 to 3 mSv depending on the protocol and the child’s size. These doses are carefully tailored to be as low as reasonably achievable (ALARA principle) to reduce any potential long-term risks.
Children are more sensitive to radiation because their cells are dividing more rapidly, and they have a longer expected lifetime during which radiation-induced effects could develop. Therefore, pediatric imaging centers use specialized protocols that adjust the radiation dose based on the child’s age, weight, and the diagnostic need. Modern CT scanners have software and hardware features that automatically modulate the dose, such as adjusting the tube current in real time based on the density of the body part being scanned.
In addition to dose reduction techniques, alternative imaging methods that do not use ionizing radiation, such as ultrasound and MRI, are preferred whenever possible for children. CT scans are reserved for situations where the detailed anatomical information they provide is essential and cannot be obtained by other means.
Radiologists and pediatric imaging specialists are trained to weigh the benefits and risks of CT scans carefully. They consider the urgency of diagnosis, the potential impact on treatment, and the cumulative radiation exposure if multiple scans are needed over time. Communication with families about why a CT scan is recommended
