What does the computer do to form an image in CT scanning?

In a CT scan, each pixel of the resulting image corresponds to a specific value that represents the attenuation of X-rays by the tissues through which they pass. The computer processes the raw data collected from the scanner and assigns a numerical value to each pixel based on the amount of radiation that is absorbed by the different types of tissue. This means that the assigned value helps in reconstructing the image by creating variations in shades of gray, which correlate with the density of the tissues. Denser tissues, like bone, absorb more radiation and thus correspond to higher values, while less dense tissues, like air or fat, appear darker.

This numerical assignment is crucial because it allows for the interpretation of the images—radiologists can determine the structure and any abnormalities by analyzing the varying pixel values. The effective representation of these values is what ultimately leads to the formation of the detailed cross-sectional images that CT scans are known for.

While combining multiple images, enhancing brightness levels, or setting patient contrast can also improve image quality and clarity, the fundamental process of image creation relies on assigning values to pixels. This pixel value assignment is central to how images are reconstructed and interpreted in CT imaging.