Allan M. Cormack, Computerized Axial Tomography (CAT)
and Magnetic Resonance Imaging (MRI)

Resources with Additional Information

magnetic resonance imaging system

Computed axial tomography, commonly known as CAT scanning, was introduced in 1972. During a CAT scan, a large coil of x-ray tubes rotates around the patient's body, taking x-rays from all angles. A computer integrates all of these x-rays into a single, three-dimensional image on a television screen. The data can be saved on the computer.

Allan M. Cormack, a high energy physicist at Tufts University, shared the 1979 Nobel Prize in Physiology and Medicine for his key work in developing the methods for CAT scanners. At the time of development, these methods were widely regarded as the most significant advance in medical radiography since the 1895 discovery of x-rays.

Magnetic Resonance Imaging (MRI) is used to localize brain activity during sensory or cognitive stimulation of the subject. Images of the subject's brain at rest and then during the performance of an intellectual task are compared to probe cognitive processes. Sir Peter Mansfield and Paul Lauterbur won the 2003 Nobel Prize in Physiology or Medicine "for their discoveries concerning magnetic resonance imaging".

CAT and MRI scanners have revolutionized diagnosis of disorders of soft tissues, especially disorders of the head and brain. Most shock-trama units or major neurological clinics have one of these machines on-site or at their immediate disposal. The sophisticated mathematical techniques used to reconstruct the images of organs and tissues that doctors see with these amazing diagnostic instruments originated in particle detection methods developed by high-energy physicists.

For more information about CAT and MRI scanners, see the database report The Ultimate Structure of Matter: The High Energy Physics Program from the 1950s Through the 1980s.

Resources with Additional Information

Additional information about Allan Cormack, Computerized Axial Tomography (CAT), and Magnetic Resonance Imaging (MRI)  is available in DOE documents and on the Web.


ECAT: A New Computerized Tomographic Imaging System for Position-Emitting Radiopharmaceuticals, DOE Technical Report, 1977

Emission Computed Tomography: A New Technique for the Quantitative Physiologic Study of Brain and Heart in Vivo, DOE Technical Report, January 1978

Advances in Diagnostic Instrumentation, DOE Technical Report, January 1980

Computed Tomography Status, DOE Technical Report, 1983

Fundamental Concepts of Digital Image Processing, DOE Technical Report, March 1983

Axial Tomography from Digitized Real Time Radiography, DOE Technical Report, January 1985

Medical Applications of Synchrotron Radiation, DOE Technical Report, October 1991


Alan Cormack
Allan Cormack
Attribution: APS Physics,
November 2004
(Volume 13, Number 10)

Additional Web Pages:

This Month in Physics History -- November 25, 1975:  Patent for Full-body CAT Scan

Nobel Lecture by Allan M. Cormack, (video)

The President's National Medal of Science, Allan M. Cormack

Physics Saves Lives:  Medical Imaging

History of MRI, International Society for Magnetic Resonance in Medicine (ISMRM)

Warming up for Magnetic Resonance Imaging

Extending the Power of Nuclear Magnetic Resonance Techniques

Magnetic Resonance Imaging Research



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