by Tess Hughes
In 1970, to solve this problem of expense and subsequent
unavailability, the American Department of Defence's Advanced
Research Projects Agency (ARPA) developed a system called ARPAnet,
between the Universities of California in Santa Barbara and Los
Angeles, the University of Utah, and SRI International. A researcher
could sit at one computer and access data from another. Networking was
By 1971 Intel had invented the microprocessor. 2300 transistors could
be found on this first chip. Unlike the integrated circuit, it had memory
and combined many components together on a single chip. These were the
'Fourth Generation Computers'39.
Computers were becoming more and more affordable.
In 1979, whole body SPECT was being performed by Jaszczak using weighted back
projection and attenuation correction. Fourier transform, phase analysis, curve
deconvolution, weighted filtered back projection and filtering were all realised