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The Development of Technology and Its Influence on Nuclear Medicine

by Tess Hughes

Link to Index Link to Introduction Link to 1940-49 Link to 1950-59 Link to 1960-69 Link to 1970-79 Link to 1980-89 Link to 1990-99 Link to 2000-Beyond Link to References

Evolution of man cartoon


           In 1951, Eckert and Mauchly developed the world's first general-purpose electronic digital computer, the UNIVAC (UNIVersal Automatic Computer). Instead of flashing lights, results could be printed out on paper. It was the first computer to use magnetic tape rather than International Business Machines (IBM's) slower punch card technology. UNIVAC became a household name in 1952 by predicting Eisenhower's presidential election and so IBM retaliated. They offered 60% discount for educational uses and quickly dominated the university market.4 The strong relationship between education and computing was forged.

UNIVAC computer photo - click to enlarge
Figure 35

      Also in 1951, the beginnings of Nuclear Medicine arose with the rectilinear scanner. Invented by Benedict Cassen, it produced an image on paper copying the scanning motion of the detector but was prone to jamming.

George Mueller - click to enlarge
Figure 47
George Mueller

      In 1952 George E.Mueller developed a more reliable system, by arcing each amplified pulse through layered paper to burn a black spot thus forming an image.6

      In 1953 Hal Anger developed the first recognised 'gamma camera' in the AEC Donner Lab at Berkley, USA. It produced images as an array by using a single, thallium impregnated sodium iodide (NaI(Tl)) screen and a sheet of x-ray film rather than in the linear fashion produced by the rectilinear scanner. It was however, very time-consuming, taking up to an hour for each image with therapeutic doses of radioactivity.4

      The Raytheon CK722 Junction Transistor, shown at the top of this old photograph, was the first mass-produced transistor and was manufactured in 1953.1

      In 1954, Bell Laboratories built the first 'Second Generation Computer' containing transistors. The more complex the circuits became, however, the more complicated and numerous were the soldered connections between transistors, and the likelihood of faulty wiring increased.37

Raytheon CK722 - click to enlarge
Figure 5
The Raytheon CK722 transistor1

David Kuhl photo - click to enlarge Figure 68
David Kuhl

      It was not until 1956 that David Kuhl developed photographic output for the rectilinear scanner. This utilised a glow-lamp and x-ray film and accentuated differences in intensity of detector signal, therefore producing images of better contrast. These advances allowed dynamic imaging of blood flow and function, rather than purely static information.6

      In 1958, Jack St. Clair Kilby of Texas Instruments, manufactured the first integrated circuit or chip. This minimised the faulty wiring problem of transistor circuits by connecting the tiny transistors during chip manufacture. The diminished distance between the transistors dramatically increased the speed of computers as well. The only connections needed were between the chips and other electronic components.38

First Integrated Circuit - click to enlarge
Figure 79
First integrated circuit

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Typical Photomultiplier tube diagram - click to enlarge
Figure 811
Typical photmultiplier tube assembly

      Also in 1958, Anger replaced the film-screen combination with a single, large field-of-view NaI(Tl) crystal and photomultiplier tube (PMT) assembly. This resulted in far greater detection efficiency. The PMT array, combined with electronic position logic circuitry, determined the location of each scintillation event as it occurred in the crystal.10

      In addition to this, the energy of the scintillations could be analysed and if outside a predetermined energy range, could be excluded from further calculation and cathode ray tube (CRT) display. The CRT display showed a pattern of light that corresponded to the scintillations occurring in the detector crystal. These brighter flashes of light were more easily recorded photographically. This improved resolution, and reduced the time of acquisition and the radiation dose required. The images were recorded on Polaroid® Film or on x-ray film, which was attached to the camera housing.10

 Typical Cathode Ray tube diagram - click to enlarge Figure 912
The cathode ray tube

      The gamma camera made its debut at a Los Angeles Nuclear Medicine Society meeting in 1958. Acceptance was slow, because manufacturers were developing and improving the rectilinear scanner. Initially using a pinhole collimator, Anger developed the multi-hole collimator. This resulted in even better image resolution when coupled with larger sodium iodide crystals and more PMT's of better quality.13 See Figure 11.

Link to Index Link to Introduction Link to 1940-49 Link to 1950-59 Link to 1960-69 Link to 1970-79 Link to 1980-89 Link to 1990-99 Link to 2000-Beyond Link to References

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