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Patent

Reconstruction method of a computed tomographic image from a few X-ray projections

TL;DR: In this article, a tomographic image of a X-ray tested tissue of body is reconstructed by calculating the absorption coefficients of picture elements constituting the tomographic plane in reference to the measured values produced by the first and second projectional distributions of Xray produced by projecting X-rays.
Abstract: A tomographic image of a X-ray tested tissue of body is reconstructed by calculating X-ray absorption coefficients of picture elements constituting a tomographic plane in reference to measured values produced by the first and second projectional distributions of X-ray produced by projecting X-ray. Accordingly, it becomes possible to reconstruct a clear tomographic image of a moving X-ray tested tissue and to make an X-ray exposure level very low by extremely shortening the time of the reconstruction of computed tomographic image. Moreover, a resolving power of measuring is substantially improved, resulting in that an accuracy of reconstructing the tomographic image may also be improved.
Citations
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Patent
12 Mar 2003
TL;DR: An implantable, rechargeable assembly comprised of an implantable device disposed within a living organism, an electrical storage device connected to the implanted device, and a thermoelectric charging assembly operatively connected to an implanted device is described in this paper.
Abstract: An implantable, rechargeable assembly comprised of an implantable device disposed within a living organism, an electrical storage device connected to the implantable device, and a thermoelectric charging assembly operatively connected to the electrical storage device. The thermoelectric charging assembly has devices for transferring thermal energy between the living organism and a thermoelectric module, for generating an electrical current from the thermal energy, for charging the electrical storage device with the electrical current, for determining the extent to which the electrical storage device is being charged with the electrical current, and for generating a signal whenever the extent to which the electrical storage device is being charged with the electrical current falls below a specified value.

230 citations

Patent
07 May 1997
TL;DR: In this article, an X-ray imaging method, and device for carrying out the method, utilizes a first imaging device to form and digitally store a series of two-dimensional Xray images in which an object to be examined is projected onto an Xray image pick-up device from different perspectives, and a second imaging device is used to form a three-dimensional image of the same object.
Abstract: An X-ray imaging method, and device for carrying out the method, utilizes a first imaging device to form and digitally store a series of two-dimensional X-ray images in which an object to be examined is projected onto an X-ray image pick-up device from different perspectives, and a second imaging device to form a three-dimensional image of the same object. Quasi three-dimensional reproduction of anatomic structures is achieved by extracting a relevant structure of the object to be examined from the three-dimensional image, calculating synthetic, two-dimensional projection images of the extracted structure, the structure being projected with the same geometrical parameters as used for the relevant structure during the formation of the individual X-ray images, forming superposition images by superposing the synthetic projection images and the X-ray images formed under the same geometrical conditions, and displaying the series of superposition images.

117 citations

Patent
25 Nov 2003
TL;DR: In this article, a parallel ray beam optical tomography system for imaging an object of interest is described, where the pattern of transmitted or emitted radiation intensities is magnified by a post specimen optical element or elements.
Abstract: A parallel-beam optical tomography system (4) for imaging an object of interest (1) includes a parallel ray beam radiation source (35) that illuminates the object of interest (1) with a plurality of parallel radiation beams (36). After passing through the object of interest (1) the pattern of transmitted or emitted radiation intensities is magnified by a post specimen optical element or elements. An object containing tube (2) is located within an outer tube (32), wherein the object of interest (1) is held within or flows through the object containing tube (2). A motor (34) may be coupled to rotate and/or translate the object containing tube (2) to present differing views of the object of interest (1). One or more detector arrays are located to receive the emerging radiation (68) from the post specimen magnifying optic. Two- or three-dimensional images may be reconstructed from the magnified parallel projection data.

76 citations

Patent
Takeshi Ozeki1, Shinichi Tsubura1
18 Jan 1985
TL;DR: In this article, a scan planning method for obtaining any tomographic image by a CT system, projection data of a plurality of parallel slices is acquired by a computed tomographic scanning device.
Abstract: According to a scan planning method for obtaining any tomographic image by a CT system, projection data of a plurality of parallel slices is acquired by a computed tomographic scanning device. The tomographic images are interpolated in accordance with the tomographic data of the slices which is obtained by the CT scanning device thereby providing the three-dimensional image data. A three-dimensional object image is then displayed on a display in accordance with the three-dimensional image data. A viewpoint for the object image changes, and an orientation angle of the object image changes in accordance with a manually input coordinate information. A slice position image representing the designated position and angle of the slice is displayed three-dimensionally in accordance with the coordinate information. The CT scanning device is controlled in accordance with the position and angle of the slice position image with respect to the object image.

69 citations

Patent
31 Aug 1987
TL;DR: In this paper, an apparatus and method for determining connected substructures within a body is disclosed, which is particularly advantageous for use in medical diagnostic imaging applications and is operable in any situation in which three dimensional signal patterns representing the value of one or more physical properties associated with the substructures within body at regularly spaced grid locations within the body are presented.
Abstract: An apparatus and method for determining connected substructures within a body is disclosed. The system and method are particularly advantageous for use in medical diagnostic imaging applications. In particular, three dimensional regions exhibiting the same tissue type are similarly labeled. The system and method of the present invention is operable in any situation in which three dimensional signal patterns representing the value of one or more physical properties associated with the substructures within a body at regularly spaced grid locations within the body are presented. A subset of the original data may then be provided to a display processor, particularly one employing gradient normal shading for display of three dimensional images. Even more particularly, the present invention is related to a method and system for determining equivalence classes of objects, the objects typically comprising one or two dimensional connected regions found in a planar slice of data from magnetic resonance imaging or x-ray tomography systems.

66 citations

References
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Patent
31 Jan 1978
TL;DR: An apparatus and method for tomographic analysis comprising a detecting system for detecting a number of radiation beams having penetrated a sectional area of a subject and producing projection data signals is described in this article.
Abstract: An apparatus and method for tomographic analysis comprising a detecting system for detecting a number of radiation beams having penetrated a sectional area of a subject and producing projection data signals; a CPU and a memory for applying a filter function to the projection data signals by a convolution integration or by a computational technique included in a filtered-back projection, thereby calculating modified projection data signals, and conducting back projection operations only with respect to points in a partial region or subsection of the sectional portion area by means of the modified projection data, thereby calculating the radiation beam absorption coefficients at said points, the integral operation used in the calculation of the modified projection data signals being limited to an interval in which the quality of an image of said partial region or subsection to be displayed can exclusively be improved by the filter function; and a display unit for displaying the image of the partial region on the basis of said absorption coefficients.

36 citations

Patent
31 Jan 1978
TL;DR: In this article, a data selecting unit which divides into a plurality of groups and stores the projection data signals provided by a multitude of radiation beams being projected along several different directions through a slice to be imaged in a subject and penetrating the slice from the external circumference of it with each of the groups corresponding to the beams penetrating along selected directions within a specific scan sector less than 180°.
Abstract: In a method and an apparatus for performing computed tomography using radiation, the apparatus includes a data selecting unit which divides into a plurality of groups and stores the projection data signals provided by a multitude of radiation beams being projected along several different directions through a slice to be imaged in a subject and penetrating the slice from the external circumference of it with each of the groups corresponding to the beams penetrating along selected directions within a specific scan sector less than 180°; a Fourier transform unit for calculating sample values for the one-dimensional Fourier transform of a projection function formed by each group of said projection data signals; a function calculating unit for calculating sample values for the one-dimensional Fourier transforms as mentioned above for a plurality of projecting directions selected outside said specific scan sector; and a reconstruction unit for calculating the absorption coefficient distribution of the radiation beams in said slice from both said sets of sample values, and a display unit.

24 citations

Patent
14 Jun 1978
TL;DR: In a computed tomography system using radiation, a large number of radiation beams are projected into a selected slice-like sectional portion of a subject to be reconstructed, in various directions as discussed by the authors.
Abstract: In a computed tomography system using radiation, a large number of radiation beams are projected into a selected slice-like sectional portion of a subject to be reconstructed, in various directions. A profile of measured projection data is obtained from the radiation beams penetrated in parallel at each given angular interval. The profile of measured projection data thus obtained is subjected to a filtering operation to produce profiles of first modified projection data. The profile of modified projection data is recasted at properly selected intervals to produce second modified projection data. This results in a remarkable reduction of the amount of weight coefficients required in an interpolation to calculate the modified projection data for a large number of picture elements defined in matrix fashion on the sectional portion.

12 citations

Patent
John L. Ryan1
09 May 1979
TL;DR: In this article, it was shown that the signals for all beams are preweighted by a factor related to the angular position of the beam in the fan, leaving only a simple scaling factor which needs to be applied for each martrix element.
Abstract: In CT scanners signals representing attenuation of radiation along beam paths through the patient may be processed by a convolution technique to give radiation absorption values for a matrix of elements in a region of interest. It the beams are distributed in a fan-shape from a focus the convolution can be applied but the signals need to be weighted by a factor related to the distance of a respective matrix element from the focus. By consideration of the geometry of a CT scanner of this kind it has been found that the weighting may be achieved more efficiently if the signals for all beams are preweighted by a factor related to the angular position of the beam in the fan, leaving only a simple scaling factor which needs to be applied for each martrix element.

11 citations

Patent
Deibitsuto Maikeru Watoson1
09 May 1979
TL;DR: In this article, the authors proposed to stretch the signals onto a line parallel to lines of matrix elements applying an angular part of the weighting common to all of the rows and leaving a straightforward stepping through the signals to be followed as they are allocated to the storage locations.
Abstract: In a CT scanner system electrical signals are provided for radiation paths in a fan-shaped distribution through a region of interest of the patient. The signals are processed and further signals derived therefrom are mapped onto elements of a matrix defined in the region by being summed in storage locations corresponding to the elements. The mapping includes weighting by a factor related to the angle of the respective beam in the fan, the factor being different for each matrix element. To achieve more efficient use of the circuits handling the signals it is proposed to stretch the signals onto a line parallel to lines of matrix elements applying an angular part of the weighting common to all of the rows and leaving a straightforward stepping through the signals to be followed as they are allocated to the storage locations.

10 citations