Digital brain imaging in the 1970s: building a hybrid technology

Abstract

Computed tomography (CT), a technology based on the combination of radiology and computation, was used to scan a patient’s brain tumor in a London hospital in 1972. The patient’s head was introduced into a scanner, manufactured by the British record company EMI, to measure the amount of radiation absorbed by different points in the brain. The resulting image consisted of a digital tonal matrix that was materialized on newsprint, a cathode ray tube, and a Polaroid photograph. This article describes the production process of the CT image, a visual representation that would become, from the 1970s onwards, a common technology for contemporary neurosciences and a paradigm of visual representation in the transition from analog to digital. To this end, we analyze the implications of the radiographic image, invented at a time of the rise of theimage-movement in which chronophotographs, image sequences, and cinematography are framed. In this analysis, we focus on the scopic regime in which each image is found. The knowledge that led to construction of the device circulated between the clinic, industry, and laboratory. A variety of agents were involved in the construction of CT scans, including the computer, X-ray radiation, a team of electronic engineers, a group of neuroradiologists from Atkinson Marley Hospital, and the X-ray scanner, among others. We also report on the impact of several factors associated with the epistemology of CT imaging, such as the reinforcement of clinical diagnoses, the linking of the morphological to the psychic in relation to the brain, and the transition from image-motion to image-time.