What type of measurements do detectors obtain to mathematically reconstruct a CT image?

Detectors in a CT scanner capture raw data, which consists of measurements of the X-ray attenuation as the beam passes through the patient's body from various angles. This data is foundational for reconstructing the images that appear on a CT scan.

When X-rays are projected through the body, some are absorbed while others pass through and are detected. The raw data comprises the intensity readings from these detectors for each angle of rotation. This information reflects the differing densities of tissues within the body and is essential for the mathematical algorithms used in image reconstruction, such as the filtered back projection or iterative reconstruction techniques.

Understanding the nature of raw data is crucial because it allows radiologists and technologists to derive detailed images that help in diagnosing and assessing medical conditions. In contrast, other options like image slices represent the outcome of processing raw data, while ray sums refer to the integration of data across specific paths, and radiation dosage pertains to the amount of radiation exposure a patient receives, none of which directly represent the measurements used for image reconstruction.