Cat Scan History

A CAT scan, also called a CT scan, uses X-rays and computer-assisted tomography to generate a 3-D image of organs, bone, soft tissue and blood vessels. Since the 1970s, this technology has provided a non-invasive alternative to exploratory surgery.

Inventors

• Allan Cormack and Godfrey Hounsfield received the 1979 Nobel Prize in Physiology or Medicine for inventing the first clinical CAT scanner for scanning the brain. In November 1975, Robert Ledley, a professor at Georgetown University, patented the whole-body CAT scan.

First-Generation CAT Scan

• The original CAT scanner required pressing the patient's head against a rubber membrane and into a water-filled box. The box rotated in 1-degree increments while a single, narrow X-ray beam and single-detector assembly collected data during a five- to six-minute scan.

Second-Generation CAT Scan

• After the first full-body CAT scanner was introduced, the image quality was greatly improved with the second-generation scanner. It used 20 or more narrow beams and detectors, which allowed a complete scan in the time the patient could hold a breath.

Third-Generation CAT Scan

• The X-ray beam was widened into a fan shape to cover the entire width of the patient. An array of 250 or more detectors was linked to the X-ray tube, which rotated together around the patient in less than five seconds.

Fourth-Generation CAT Scan

• By 1976, scanning in a mere second was achieved using a large, stationary ring of detectors that required only the X-ray tube to rotate around the patient.

Modern CAT Scan

• Current CAT scan designs can complete a scan in as little as one-third a second.