Medical imaging techniques like CT scans use calculus concepts, especially integration, to combine many X-ray measurements taken from different angles around the body into a single detailed image. This process is based on the Radon transform, developed by Joseph Radon in 1917, which uses integrals to reconstruct the inside of the body by adding up (integrating) the signals along various paths. Thanks to these ideas, doctors can create clear pictures from complex data, helping them diagnose and treat patients without surgery.