摘要:
A radiographic imaging apparatus includes a radiation detector (16) and a radiation source (12) which projects a non-parallel beam of radiation into field of view (14). A footprint of each voxel (v) which is projected on the detector (16) is corrected based on the position of the voxel (v) in the field of view (14) in relation to the radiation detector (16) and the radiation source (12). The contributions from substantially parallel redundant projections are further combined based on a fractional distance frac from a center point (82) of the voxel (v) to a center of each of the adjacent redundant projections.
摘要:
A radiographic imaging apparatus includes a radiation detector (16) and a radiation source (12) which projects a non-parallel beam of radiation into field of view (14). A footprint of each voxel (v) which is projected on the detector (16) is corrected based on the position of the voxel (v) in the field of view (14) in relation to the radiation detector (16) and the radiation source (12). The contributions from substantially parallel redundant projections are further combined based on a fractional distance frac from a center point (82) of the voxel (v) to a center of each of the adjacent redundant projections.
摘要:
The invention relates to an imaging method, especially a computerized tomography method, with which an object is penetrated by rays from different directions and measured values, which depend upon the intensity of the rays after penetrating the object, are acquired by a detector unit. From these measured values, an object image is reconstructed by means of back projection of measured-value-dependent back projection values. Therein, the object image is divided into overlapping, quasi-spherically symmetric image segments, each being defined by an image value and a quasi-spherically symmetric base function. Furthermore, during the back projection, the back projection values are added in proportions to the image values, wherein the proportion of a back projection value, which is added during the back projection to an image value, is dependent on a proportionality factor, which is equal to the average value of the line integrals of the base function belonging to the respective image value along those rays that have generated the measured value, on which the respective back projection value is dependent.
摘要:
The invention relates to an imaging method, especially a computerized tomography method, with which an object is penetrated by rays from different directions and measured values, which depend upon the intensity of the rays after penetrating the object, are acquired by a detector unit. From these measured values, an object image is reconstructed by means of back projection of measured-value-dependent back projection values. Therein, the object image is divided into overlapping, quasi-spherically symmetric image segments, each being defined by an image value and a quasi-spherically symmetric base function. Furthermore, during the back projection, the back projection values are added in proportions to the image values, wherein the proportion of a back projection value, which is added during the back projection to an image value, is dependent on a proportionality factor, which is equal to the average value of the line integrals of the base function belonging to the respective image value along those rays that have generated the measured value, on which the respective back projection value is dependent.
摘要:
The invention relates to a device and a method for the iterative reconstruction of the attenuation coefficients μj in a tomographic image of an object (1) from projection measurements mi. In the update equation for μjn during the n-th iteration the backprojected error (mi−mi−(μjn)) is weighted by a voxel dependent factor Formula (I). Such a voxel dependent update may particularly be included in the algorithms of ART or ML.
摘要:
A device (1) for imaging the interior of an optically turbid medium is provided. The device comprises a receptacle (3; 103) structured to accommodate an optically turbid medium for examination and an optically matching medium filling a space between an inner surface (6; 106) of the receptacle (3; 103) and the optically turbid medium. The device comprises at least one light source generating light to be coupled into the receptacle (3; 103) and at least one detector for detecting light emanating from the receptacle (3; 103). A coupling surface (10; 110) optically coupled to the inner surface (6; 106) of the receptacle and a coupling member (11; 111) optically coupled to the light source and the detector are provided. The coupling surface (10; 110) and the coupling member (11; 111) are movable to a plurality of different positions relative to each other and structured to establish an optical connection from the light source to the inner surface (6; 106) of the receptacle and from the inner surface (6; 106) of the receptacle to the at least one detector in the plurality of different positions.
摘要:
The invention relates to a system, a medical image acquisition system, and a method for imaging an interior of a turbid medium (25). The invention also relates to a marker (60) for use in the method for imaging an interior of a turbid medium (25). The system, the medical image acquisition system, and the method may be used for obtaining an image of an interior of a turbid medium (25) by: accommodation of a turbid medium (25) inside a receiving volume (20); irradiation of the receiving volume (20) with light from a light source; detection of light emanating from the receiving volume (20) as a result of irradiating the receiving volume (20) with light from the light source through the use of a photodetector unit. The detected light is then used to reconstruct an image of an interior of the turbid medium (25). According to the invention, the system, the medical acquisition system, and the method are adapted such that during a measurement the receiving volume (20) comprises at least one marker (60) comprising a predetermined concentration of a chosen fluorescent agent. The light source is arranged for generating excitation light that causes fluorescent emission in the marker (60) and the photodetector is arranged to detect light emanating from the receiving volume (20) as a result of irradiating the receiving volume (20) with excitation light. The use of a marker (60) according to the invention enables obtaining information relating to the geometry of the turbid medium (25). If the turbid medium (25) comprises an unknown concentration of a second fluorescent agent, and the light source and the photodetector unit are arranged for causing fluorescence in the second fluorescent agent and detecting the resulting fluorescence light, respectively, the use of a marker (60) according to the invention enables calibration of the signal resulting from this fluorescence light.
摘要:
A device (1) for imaging the interior of an optically turbid medium is provided. The device comprises a receptacle (3; 103) structured to accommodate an optically turbid medium for examination and an optically matching medium filling a space between an inner surface (6; 106) of the receptacle (3; 103) and the optically turbid medium. The device comprises at least one light source generating light to be coupled into the receptacle (3; 103) and at least one detector for detecting light emanating from the receptacle (3; 103). A coupling surface (10; 110) optically coupled to the inner surface (6; 106) of the receptacle and a coupling member (11; 111) optically coupled to the light source and the detector are provided. The coupling surface (10; 110) and the coupling member (11; 111) are movable to a plurality of different positions relative to each other and structured to establish an optical connection from the light source to the inner surface (6; 106) of the receptacle and from the inner surface (6; 106) of the receptacle to the at least one detector in the plurality of different positions.
摘要:
The invention relates to a computed tomography apparatus for imaging an object. The computed tomography apparatus comprises a radiation source (2) for generating modulated radiation (4) traversing the object and a detector (6) for generating detection values depending on the radiation (4) after having traversed the object, while the radiation source (2) and the object are moved relative to each other. A weight providing unit (14) provides modulation weights for weighting the detection values depending on the modulation of the radiation (4) and a reconstruction unit (15) reconstructs an image of the object, wherein the detection values are weighted based on the provided modulation weights and an image of the object is reconstructed from the weighted detection values. This can allow to optimize the dose application to the object by modulating the radiation accordingly, wherein the reconstructed images still have a high quality.
摘要:
A method includes reconstructing measured projection data using an iterative statistical reconstruction algorithm that reduces image artifact caused by differences in variances in projections of the measured projection data used to update a voxel of the image for one or more voxels of the image. A reconstructor includes a processor that reconstructs measured projection data using an iterative statistical reconstruction algorithm that reduces or mitigates image artifact caused by differences in variances in projections used to update a voxel of the image for one or more voxels of the image. A computer readable storage medium encoded with computer executable instructions, which, when executed by a processor of a computer, cause the processor to: reduce image artifact caused by differences in variances in projections used to update a voxel of an image for one or more voxels of the image using an iterative statistical reconstruction algorithm.