APPARATUS FOR DISPLAYING A SECTION OF A BODY SUBJECTED TO PENETRATING RADIATION IN PARTICULAR X RAYS OR GAMMA RAYS

摘要

1525612 Radiography THOMPSON-C S F 12 Sept 1975 [13 Sept 1974] 37689/75 Heading H4F The invention relates to a television system for a computed tomography system in which a crosssection of a body is to be displayed in a pattern of opacities to radiation related to elements of a notional matrix overlying the cross-section, and the television system is capable of displaying those elements with opacities lying within an adjustable range centred on a selectable value to be displayed distinctly from all other areas, e.g. with different contrast and/or colour. For example, Fig. 9 shows a computed tomography signal processing system comprising a data store 4, a computer 9 and a digital-to-analogue converter 12 which applies a modulating voltage to the control grid of a c.r.t. 31. The opacity range and central value are applied to register 14 and comparators 131 and 132 determine whether a signal value from store 4 lies within or outside the range. If it is not within the range, gate 40 is blocked and inverters 41, 44 and gates 34, 39 apply a voltage V, to the anode 32 of the c.r.t. such as to give a green display with a contrast determined from a register 11. If the signal lies within the specified range, however, anode voltage V 2 is applied by gate 35 so as to give a red display, the contrast value then being that from register 45 because gate 46 is activated. In monochrome displays, the areas outside the range of interest can be displayed as all white or all black.