CT Scan Principles
A CT scan (computed tomography) combines many X-ray images taken from different angles to build highly detailed cross-sectional views of the body. It lets doctors see inside organs with clarity.
How CT images are built
In a CT, the X-ray tube rotates around the patient while the table moves slowly. Detectors on the opposite side measure how much radiation is absorbed from each angle. A computer processes this data into cross-sectional images.
Each thin cross-section is called a slice. From hundreds of slices, the computer can build two-dimensional and three-dimensional reconstructions to aid diagnosis.
Advantages over a standard X-ray
A standard X-ray overlaps all structures in one picture, so organs hidden behind bone can be hard to see. CT separates these structures into slices, making fine details easier to distinguish.
CT is also very fast, making it suitable for emergencies such as head injury or suspected stroke.
Contrast and dose
Intravenous contrast is often used to highlight blood vessels and specific organs. CT doses are generally higher than a standard X-ray, so the indication should be carefully considered.
Modern facilities use low-dose protocols and optimization techniques to reduce exposure without compromising diagnostic quality.
Key points
- It gives more detail than a standard X-ray.
- Images can be viewed as thin slices and 3D reconstructions.
Educational information, not a substitute for medical advice.