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September 22, 1975

Computerized Tomography of the Head

Author Affiliations

From the departments of diagnostic roentgenology (Drs Baker, Houser, Reese, and Holman) and neurology (Dr Campbell), Mayo Clinic and Mayo Foundation, Rochester, Minn.

JAMA. 1975;233(12):1304-1308. doi:10.1001/jama.1975.03260120066029

COMPUTERIZED tomography is a recent exciting radiologic innovation for diagnosing intracranial lesions. It was developed by Godfrey N. Hounsfield, a senior research scientist at Central Research Laboratories, EMI, Hayes, Middlesex, England.1-6 A narrow moving beam of x-rays is passed through the head and attenuation coefficients of small units of brain are plotted by computer as the beam traverses the cross section of the tissue that is scanned. The system, in essence, produces a series of displays of axial tomograms or slices. It is capable of detecting minute alterations in absorption values of the intracranial contents. The clinical usefulness of the instrument has been reported recently by several authors.7-16

The Scanner  The basic EMI scanner system includes a scanning unit (containing the x-ray tube and accurately aligned radiation detectors), an x-ray generator and controls, a computer with magnetic disk unit and printer, and cathode-ray tube viewing unit.The