Abstract: Apparatus is described for performing a computerized axial tomographic examination of a body. The apparatus contains a source of x-radiation and detector devices mounted to face one another across an opening for the body, the source being arranged to project said radiation in a plane towards the detector devices. The source and detector devices are rotated about an axis passing through said opening and means are disclosed for locating the body in said opening and for adapting the apparatus to accommodate a body which is not centrally located in said opening.

Abstract: The invention relates to apparatus for examining a body by means of penetrating radiation in which a source of radiation produces a beam of radiation which passes through the body, and a detector receives the radiation emerging from the body. The source and the detector are mounted on a scanning structure which can undergo successive lateral scans at a succession of orbital positions so that a plane section of the body is traversed by a set of parallel beams at each of the orbital positions. A reference attenuator provides a known attenuation of the beam at the beginning of each lateral scan, and means are provided for modifying the output signals during each lateral scan in response to the signal obtained when the beam is passing through the reference attenuator. In this way compensation is effected for rapid changes in the sensitivity of the detector.

Abstract: In a radiological apparatus, arranged to produce a representation of the variation of absorption of penetrating radiation over a planar, cross-sectional slice of a body under examination, the radiation emergent from the body along a plurality of paths in the plane of the slice is detected by detector means including one or more photomultipliers. The output signals from the photomultiplier or photomultipliers are monitored and compared with upper and lower threshold levels which represent the extremes of substantially linear operation of the photomultiplier or photomultipliers. In the event of the output signals departing from the range defined by said threshold levels a correction signal is generated and utilised to tend to restore the output signals within said range.

Abstract: In radiographic apparatus arranged to investigate a region of a body which can include a moving member, for example the heart of a human patient, means are provided for compensating (at least in part) for the blurring of the radiograph which might be caused by the motion of said member. The motion of the member is monitored and used either to periodically interrupt the irradiation of the body each time the motion becomes too great or enable information which might be confused, due to the motion, to be rejected before the radiograph is produced.

Abstract: An apparatus is disclosed for examining a body by means of penetrating radiation in which the radiation is provided in the form of a sector subtending a predetermined angle at the radiation source and detected by an array of detectors in the plane of the sector. The source and detectors are scanned laterally in the plane of the sector and orbited about an axis perpendicular to that plane at an angular rate which takes account of the angle subtended by the sector. Output signals produced by the detectors related to radiation incident at different angles in the sector during the scanning movements, are used to construct a distribution of absorption coefficients for a planar slice of the body.

Abstract: Apparatus for examining a body by means of radiation such as X or .gamma. radiation includes a source of a substantially planar, sectoral-shaped swath of said radiation, collimator means having a plurality of apertures formed therein through which respective finger-like beams of the radiation can pass. The beams follow respective linear paths through a region of interest and toward detector means located on the opposite side of said region to the source; the detector means including a respective detector device for each of said finger-like beams. Conveniently each device consitutes a scintillator device and an associated photomultiplier tube, and the tubes associated with adjacent scintillator devices are misaligned to accommodate their widths. Means are also provided for orbiting the apparatus relative to said region of interest.

Abstract: The invention provides apparatus for examining bodies by means of penetrating radiation such as X- or .gamma.- radiation. The radiation is directed toward the body in a sectoral-shaped swath and the radiation emergent from the body is collected by detector devices. Each device comprises a scintillator crystal which is arranged to respond to the receipt of the radiation by emitting visible light. The devices are irradiated simultaneously and then interrogated in sequence so that the light emitted by respective ones of the devices, which is in each case indicative of the amount of radiation incident thereon, can be identified as to its origin.

Abstract: A data processing arrangement includes first storage means having storage locations arranged in a plurality of rows and second storage means comprising a single column of locations, one location being provided in said second storage means for each row of the locations in said first storage means. In order that the data stored in the two storage means can be correlated such that a combination of the data held in various locations of the first storage means can be compared with a corresponding value in a location of said second storage means, there is provided means for shifting the data held in the first and second storage means, at individually controllable rates, along said rows and said column respectively.

Abstract: Apparatus for examining a human patient by means of penetrating radiation has a source of radiation for producing a sectoral swath of radiation which traverses a planar slice of the patient and is then measured by a bank of detectors each of which is sensitive to a narrow beam of the radiation in said swath. The swath of radiation is produced by a rotating anode Coolidge tube and means are provided for monitoring the radiation intensity at spaced positions across the width of the swath and for taking account of variations of the intensity in the output signals derived from the detectors. Preferably radiation emitted from the anode at near tangential directions is selected to form the swath.

Abstract: Apparatus for examining a body by means of penetrating radiation includes a source of the radiation, disposed to irradiate the body, and detector means, responsive to the radiation, disposed to receive radiation emergent from the body. The source and detector means are scanned relative to the body, the scanning motion including a rotation of the source and detector means around the body. An attenuating mass is disposed between the source and detector means and rotates therewith so as to present substantially the same profile to the radiation when the source and detector means assume different angular positions with respect to the body.

Abstract: Radiographic apparatus is described in which a thin planar slice of the body is examined by a swath of penetrating radiation such as X-rays. Collimators are provided for collimating the radiation after it has passed through the body into a set of beams which are directed into respective detectors. The swath of radiation, the collimeters and the detectors are orbited in the plane of the slice so that the beams pass through the body from many different angular directions. Means are provided for additionally displacing at least the collimators relative to the source so that the relative position of the beams and gaps between the beams are changed during the orbital movement.

Abstract: Apparatus is disclosed for providing a visual representation of the absorption or transmission coefficients of the elements of a two dimensional matrix of elements notionally defined in a cross-sectional plane through a body. The representation is in the form of an analogue display comprising superimposed lines of information scanned on the surface of a suitable screen, the brightness of each line being indicative of the absorption suffered by penetrating radiation on traversing a respective path through said plane of the body. The orientation of each scanned line depends on the orientation of the respective path with respect to the body.