Appendix B

Historical Look at Specific Features of Computed Tomography Scanners, 1973 to 1983

YEAR DEVELOPMENTS
1973 EMI is sole manufacturer and delivers 60-head computer tomographs with 6.5-minute scan time.
1974 Siemens brings similar unit, Siretom, to clinical use as first x-ray company; Ledley presents his whole-body ACTA scanner, which is built by Pfizer in the following year; Ohio Nuclear announces the whole-body Delta-Scan 50 with 2.5-minute scan time; Artronix announces a rotation system for a 9-second computer tomograph with water-compensating body.
1975 EMI presents the 60-second head unit CT 1010 and the 20-second whole-body computer tomograph 5005; GE presents a 10-second mamma unit CT/M with rotation system as pilot project, announces the 5-second whole-body unit CT/T and sells the 270-second head unit CT/N of the Neuroscan Company; Siemens takes the Delta-Scan 50 into the worldwide sales program (apart from United States and Canada) and afterward the following Delta-Scan types as well, up to 1977.
1976 Ohio Nuclear introduces the 18.8-second Delta-Scan 50 FS, Pfizer the 20-second computer tomograph 0200 FS, and Philips the 20-second Tomoscan, and thus follow the EMI unit CT 5005; Syntex shows a 12-second whole-body computer tomograph with translation-rotation system that is, however, dropped in the following year; Elscint introduces the 10-second whole-body computer tomograph Scanex (also with translation-rotation); AS & E presents the ring detector system for 5-second scan time; Siemens introduces the Somatom with crystal semiconductor detector and instant image.
1977 Ohio Nuclear comes in the spring with the Delta-Scan 2000 series and thus “shoots down” the Delta-Scan 50 FS prematurely; three manufacturers announce at the RSNA meeting at the end of the year ring detector systems without showing image results: EMI, Picker, and Artronix; Philips announces the 5-second whole-body Tomoscan 300 and thus makes the just-available Tomoscan 200 into a special offer unit; Syntex 60 is added to the Philips sales program as neurocomputer tomograph Tomoscan 100; Syntex drops out of the computed tomography field in the following year; CGR takes over the sale of the Pfizer units and afterward those of the Varian scanner and brings the 20-sec head unit ND 8000 onto the market.
1978 Syntex, AS & E, Searle “bail out”; Pfizer takes over technology and production of the AS & E scanner; EMI distributes Searle computer tomographs because their own CT 7070 is not yet ready; Elscint exploits the translation-rotation system up to a minimum scan time of 5.8 seconds.
1979 CGR announces its own whole-body unit CE 10,000 with 1024 xenon detectors, of which the first head scans were shown only 2 years later; Siemens is successful in breaking through to the American market with the Somatom 2; all x-ray firms except for Picker prefer the rotation system with the traveling detector.
1980 EMI drops out of the computer tomography field; GE takes over the service, apart from in the United States and Canada, where Omnimedical takes over servicing and finally continues in the following year with the CT 7070 modified as Quad 1; Elscint brings a hybrid computer tomograph onto the market with the Exel 1002 with translation-rotation for high resolution and 1.9-second rotation with only 280 detectors; Pfizer shows CT images from its new ring detector with 2400 elements and a resolution of 0.4 mm.
1981 Pfizer “bails out”; Picker is taken over by the British GEC; GE and Siemens present at the RSNA meeting the CT 9800 and the Somatom DR, with minimum scan times of 1.3 and 1.4 seconds, respectively.
1981 to 1983 Eight manufacturers still represented with worldwide activities; among these, GE has the peak position in the United States, Siemens in Europe, and Toshiba in Japan.

From Dümmling K: 10 years’ computed tomography: a retrospective view, Electromedica 52:13-28, 1984.