“During the late 1960s and the early 1970s, John Mallard’s remarkable research group at the University of Aberdeen introduced their version of an emission tomograph (figure2) that used discrete scintillation detectors, the Aberdeen Section Scanner (ASS)”
https://pdfs.semanticscholar.org/1ffd/eaf20266c0a1c7cd70239218746a0b972f56.pdf
REFERENCES:
https://pdfs.semanticscholar.org/1ffd/eaf20266c0a1c7cd70239218746a0b972f56.pdf