コンピュータ断層撮影

CT uses an X-ray source that rotates around the body, emitting rays through thin cross-sections while a detector captures signals to build 2D slice images. Multiple slices are then combined by computer processing to form a complete 3D image of the scanned region, providing detailed anatomical visualization.

Unlike traditional X-ray imaging, CT can clearly distinguish structures with similar densities by combining multiple cross-sectional images. CT also provides detailed 3D visualization and can analyze bone defects, clots, and tumors with precision, whereas standard X-ray produces only a single 2D projection.

Hounsfield units measure the intensity of X-rays absorbed by tissues, providing a relative quantitative measurement of radiodensity used to interpret CT scans. This standardized scale allows physicians to distinguish between different tissue types based on their density characteristics and identify abnormalities with precision.

Software can reformat the 2D image slices obtained during a single scan to display different anatomical planes, including sagittal and coronal views in addition to the standard axial plane. This capability eliminates the need for additional X-ray exposures when examining different anatomical perspectives.

CT scanning is especially useful for soft tissue imaging in the brain, thoracic, and abdominal regions. Its precision allows physicians to measure tumor masses or tissue down to a millimeter and detect bone defects, clots, and other abnormalities with exceptional detail.

CT scanning exposes patients to radiation doses many times higher than traditional X-rays. Children undergoing CT scans face increased cancer risk, and adults with multiple CT scans also experience elevated risk, making careful clinical justification essential for this imaging modality.

More powerful computers and sophisticated software have made CT scanning routine for diagnostic evaluations. These advances enable rapid image processing, multi-planar reconstruction, precise tumor measurements, and detailed soft tissue visualization, transforming CT into an indispensable tool for modern medical imaging.