Thomson-csf

Compagnie Generale De Radiologie

Remy Klausz

Rene Chekroun

Marcel Bloch

Jean Bens

A method is disclosed for eliminating the diffused radiation in a radiology image. The method fundamentally consists in interposing a mask comprising a finite number of areas absorbent to X-rays between the X-ray source and the object which is to be examined, in detecting the corresponding fundamental image in order to deduce from the areas of the same which correspond to the parts eliminated from the beam a distribution of the diffused radiation throughout the image, and in correcting the fundamental image based on this distribution. The method is particularly applicable to medical radiology.

Method for eliminating the diffused radiation in a radiology image

A process for tomodensitometric image display in the dynamic mode, and a tomodensitometer utilizing the process in medical radiology. The invention relates to a process and to a tomodensitometer for the real-time and simultaneous generation of several images at instants close to each other of one and the same plane cross-section of a body under examination. After appropriate processing, each projection obtained from a source of radiation passing through the plane cross-section to a receiver is fed to a calculator of the contributions of the projection at a given point of the cross-section. The contribution is supplied to a multiplexer which feeds the same to accumulator memories, each being allocated to an image of the cross-section at a given instant.

Tomodensitometer for image display in the dynamic mode

Tomodensitometer, particularly for examining bodies which perform cyclic movements such as the heart and the pericardiac tissues. To eliminate blurring caused by the heart movements the rotation of the radiodensitometric measuring system is synchronized with the movements in such a way that at the time when the periodic movement of the tissue is at its maximum amplitude the projection direction substantially coincides with the direction of the movement and that the start and finish of the measurements coincide respectively with the start and finish of the immobility periods adjacent to the movement period.

Tomodensitometry process and tomodensitometer suitable for this process

A reference detector device for a multidetector tomodensitometer comprises several reference detectors. It also comprises filters reproducing the most current objects as regards X-ray attenuation. Each reference detector is associated with one of the filters. A reference value, at a given instant, is obtained by a combination of the values detected at the same instant on different reference detectors.

Reference detector device for a multidetector tomodensitometer and

Means for locating accurately without ambiguity tomodensitometric sections sloping in any way with respect to an original predetermined plane. At least one locating element is disposed on the part to be examined by conventional tomodensitometry, this element having a baseline situated in the original plane and having at least one characteristic such as density, varying continuously or substantially continuously along a direction perpendicular to this baseline, the variation of this characteristic being measurable on the tomodensitometric images of the different sections; this characteristic may be in particular a dimension of the element: width perpendicular to the direction perpendicular to the base in the case where the element is a triangle.

Device for the accurate anatomical locating of tomodensitometric sections

The invention relates to a method of optical storage of a numerical image and to methods of analog read-out and numerical processing of an image thus stored as well as to systems which make use of said method. All the digits of a given rank of the numbers constituting the numerical image are recorded on the same medium consisting of a film, for example, in the form of juxtaposed surface elements which, in a given example, are made conventionally opaque to light when the corresponding digit is either 1 or 0 and only in this case in order to constitute a sub-image. A surface element associated with one digit occupies a position within the sub-image which is similar to the position occupied by the number containing said digit in the numerical image.

Method and apparatus for optical storage of numerical images, and

Ionization chamber detector making it possible to eliminate stray signals generally due to deformations of lines of force of the electrical field created between the electrodes of the ionization chamber, the deformations being located at the ends of the electrodes. The detector comprises an ionization chamber sealingly subdivided into at least two compartments by means of a dielectric material partition which is permeable to the ionizing radiation beam, the compartments being successively arranged on the path of the beam. The downstream compartment contains the measuring electrodes and the upstream compartments the guard electrodes, which are respectively coplanar and are raised to the same potentials as the measuring electrodes. The gases introduced into both compartments at the same high pressure have different atomic numbers.

Ionization gas detector and tomo-scanner using such a detector

The invention relates to a novel process for the use of a transverse axial tomo-scanner in such a way that it can be used for carrying out cinedensigraphy. Instead of measuring the different projections of the cross-section during examination as a function of the different angular positions of the radiation absorbing device, the same projection (i.e. with a fixed device in the plane of the section) is measured at different times constituting a sampling of the phenomenon to be observed. It is thus possible to visually display the evolution in time of cyclic or non-cyclic phenomena by using equipment which is not, a priori, intended for this purpose.

Process for use of an X-ray tomo-scanner making it possible to perform

A tomodensitometric apparatus for the radiological examination of an object by relative rotation with respect to said object of a fixed array consisting of a source of penetrating radiation and a plurality of detectors disposed along a line. In order to correctly position the object in the center of the radiation field prior to the examination and without subjecting the object to a dose of test radiation, the invention provides a movable screen which is placed between the source and the object to be examined. The dimensions of the screen are such as to prevent the radiation emanating from the source from reaching any but at least one of the two outermost-lying detectors in the line of detectors. When the array is rotated in a test cycle, the signals from the one or two outermost detectors are received by a suitably programmed computer which generates a displacement schedule that is transmitted to the controller and displaces the object in the direction necessary to move it to the center of the radiation field.

Method and apparatus for automatically centering an object for

Radiographic apparatus reconstituting an image by processing by means of a computer the signals delivered by a detector measuring the coefficient of absorption of a body through which an X-ray beam passes. A plurality of detectors disposed in a fan arrangement are used, whereby it is possible to decrease the number of scanning stations. According to the invention, this number of stations is an odd number for a complete revolution. Further, a number of detectors in excess is used for a given included angle of the fan arrangement so that the response of defective detectors can be eliminated.

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Paris, France

Remy Klausz