63 results about "Calibration phantom" patented technology

Provided is a calibration method for calibrating a scanning and imaging device. The calibration method comprises: by means of a detector, collecting rays which have passed through a geometric calibration phantom so as to obtain detector data, the detector data comprising an actual projection position of the rays on the detector after the rays have passed through the geometric calibration phantom; obtaining initial ray source parameters and initial detector parameters; according to the initial ray source parameters, the initial detector parameters, and the positional relationship of the geometric calibration phantom with respect to a ray source and the detector, obtaining a theoretical projection position of the geometric calibration phantom on the detector by means of geometric calculation; constructing an optimization function of the deviation between the actual projection position and the theoretical projection position in terms of the ray source parameters and the detector parameters; and according to the optimization function, determining the ray source parameters and the detector parameters which correspond to the minimum deviation value as optimized ray source parameters and optimized detector parameters, and determining the optimized ray source parameters and the optimized detector parameters as geometric calibration parameters.

The invention discloses a plane CT geometric calibration method, system, storage medium and device, and the method comprises the following steps: obtaining a plane CT to scan a calibration model body, so as to obtain a projection image of the calibration model body; the calibration die body comprises a body and a plurality of pairs of calibration small balls arranged on the body, and the plurality of pairs of calibration small balls are configured to be of a two-layer structure; wherein a sphere center connecting line of each pair of calibration small balls is perpendicular to a detector receiving plane of the plane CT; processing the obtained projection image to obtain projection coordinates of each calibration small ball; pairing the calibration balls based on the projection coordinates of each calibration ball, and determining a projection coordinate connecting line of each pair of calibration balls; determining vertical point coordinates of a radiation source focus in the plane CT in the receiving plane of the detector based on each projection coordinate connecting line; and adjusting the position of the radiation source or the detector to enable the vertical point of the radiation source to coincide with the plane center point of the detector, thereby completing calibration. The method is easy to operate, the plane CT geometric calibration precision can be effectively improved, and the calibration workload is reduced.

The present invention relates to the technical field of CT, and discloses a dual-energy-spectrum material decomposition calibration phantom and method. The dual-energy-spectrum material decomposition calibration phantom comprises an organic glass cylinder having a length of 16 cm, two Teflon cylinders having different diameters are embedded in the organic glass cylinder, and the diameters of the two Teflon cylinders are respectively one third and one fourth of the diameter of the organic glass cylinder. According to the dual-energy-spectrum material decomposition calibration phantom and method, calibration is performed on a projection, without relying on an image reconstruction process, so that energy spectrums and original projection data information can be more fully utilized, so as to obtain a more accurate image and a more accurate material decomposition result.

The invention discloses an absolute quantitative correction method and device for medical imaging equipment, and relates to the technical field of nuclear medical imaging equipment correction. When the method is executed, the actual activity concentration of the calibration die body injected with the first known tracer activity serves as the first activity concentration; then, the calibration die body injected with the first known tracer activity is collected in medical imaging equipment, and the activity concentration in a first image domain obtained through calculation serves as second activity concentration; and finally, calculating a correction factor based on the first activity concentration and the second activity concentration, wherein the correction factor is used for correcting absolute quantification of the medical imaging equipment. Therefore, the correction factor is calculated by comparing the activity concentration calculated by the medical imaging equipment with the actual activity concentration of the calibration die body, so that the medical imaging equipment can accurately adjust the measurement result according to the correction factor during subsequent absolute quantitative analysis; the effect of improving the absolute quantification accuracy of the medical imaging equipment is achieved.

Provided is a calibration method for calibrating a scanning imaging device, comprising: when a geometric calibration phantom is located in a scanning area formed by rays, executing a geometric calibration step, which comprises: collecting rays that pass through the scanning area by means of a detector to obtain detector data; performing calibration on a ray source parameter and a detector parameter by utilizing the detector data, so as to obtain an optimized ray source parameter and an optimized detector parameter, and determining the optimized ray source parameter and the optimized detector parameter as geometric calibration parameters; and when an energy spectrum calibration phantom is located in a scanning area formed by rays, executing an energy spectrum calibration step, which comprises: collecting rays that pass through the scanning area by means of the detector, and obtaining real projection data related to the energy spectrum phantom; and performing calibration on an energy spectrum parameter according to a geometric relationship and a physical attribute of the energy spectrum calibration phantom by utilizing the actual projection data, so as to obtain an optimized energy spectrum parameter, and determining the optimized energy spectrum parameter as an energy spectrum calibration parameter.

A system generates a navigation space and a virtual space including a calibration phantom including a protrusion pair or a single protrusion based images. The system also identifies sets of coordinates in the virtual space based on an imaging device projection intersecting the protrusion pair or the single protrusion and determines an optimal set of coordinates in the virtual space based on a first event in which the imaging device projection intersects the midpoint of each protrusion of the protrusion pair or based on a second event in which the imaging device projection intersects a tip portion of the single protrusion. The system further calibrates a first coordinate system associated with the virtual space with respect to a second coordinate system associated with the navigation space in response to the first event and based on the optimal set of coordinates.

Provided in the present disclosure is a calibration method for performing energy spectrum calibration on a scanning imaging device, which comprises: when an energy spectrum calibration phantom is located in a scanning area formed by rays, obtaining a geometric relationship between a ray source, the energy spectrum calibration phantom, and a detector according to relative positions of the ray source, the energy spectrum calibration phantom, and the detector; collecting rays that pass through the scanning area by means of the detector to obtain real projection data; obtaining a physical attribute of the energy spectrum calibration phantom, wherein the physical attribute is pre-determined according to the material of which the energy spectrum calibration phantom is made or is calculated according to an image reconstruction method; calculating theoretical projection data using a plurality of predetermined basis spectra on the basis of the physical attribute of the energy spectrum calibration phantom and the geometric relationship; performing calibration on an energy spectrum parameter according to the theoretical projection data and the actual projection data, so as to obtain an optimized energy spectrum parameter; and determining the optimized energy spectrum parameter as an energy spectrum calibration parameter.

The invention relates to the technical field of image processing, and discloses a CT system geometric parameter correction device and correction method.The CT system geometric parameter correction device comprises a CT system and a calibration die body, and the CT system is used for bearing a measured object or the calibration die body; the calibration die body comprises a mounting plate, an adjusting structure, a calibration structure and two identification pieces; the adjusting structure is connected to the mounting plate, the calibration structure is connected to the adjusting structure, the two identification pieces are arranged on the calibration structure, and the two identification pieces are oppositely arranged in a diagonal mode. A ray source center light beam of the CT system in an error-free state passes through the centers of the two identification pieces and the center of the detector. According to the method, the geometric parameters of the measured object at different positions can be accurately calculated, so that the calibration precision of the geometric parameters is ensured, and the quality of a reconstructed image is improved.

The present invention provides a generation method for calibration data. The calibration data is used for correction of image reconstruction of a scanning imaging device. The method comprises: placing a calibration phantom in a scanning area formed by rays, wherein the calibration phantom comprises M sections respectively composed of M materials, the M materials have M physical property theoretical values, respectively, and M is a positive integer greater than or equal to 2; by means of a detector, collecting rays passing through the scanning area so as to acquire actual projection data; on the basis of the actual projection data, using an image reconstruction algorithm to reconstruct the calibration phantom to obtain a reconstructed image; performing segmentation processing on the reconstructed image to obtain M reconstructed sub-images, wherein the M reconstructed sub-images respectively correspond to the M sections; for the M reconstructed sub-images, respectively calculating M physical property measurement values corresponding to the M sections; and generating calibration data on the basis of the M physical property theoretical values and the M physical property measurement values.

An intraoral tomosynthesis imaging apparatus having an intraoral detector coupled to a frame or radio-opaque marker attached to its radiation facing surface without any frame attached, wherein the frame defines a target aperture for an incident radiation beam. An enclosure seats against the target aperture and houses at least one x-ray source configured to emit a radiation beam from each of a plurality of focal points within the enclosure A collimator is disposed to form a collimated radiation beam and direct the collimated beam through the target aperture and to the detector. A geometric calibration phantom having a plurality of radio-opaque markers is disposed in the path of the collimated beam. This arrangement is modified to operate as a regular intraoral imaging device by accommodating a high-power central source at the same or different distances as other sources from the detector and displacing the phantom from the field of view.

Provided are a calibration method and a calibration apparatus for an imaging device and an imaging device, which can be applied to the technical field of security checks and the field of medical diagnosis. The method comprises: calculating a first theoretical intersection line according to a theoretical position of a target point of a radiation source of the imaging device, a theoretical detection position of a detector, and a phantom position of a calibration phantom (S210); determining first detection projection information for the calibration phantom on the basis of the first theoretical intersection line, an attenuation coefficient of rays emitted by the radiation source in the calibration phantom, and ray energy spectrum distribution of the radiation source in the imaging device (S220); and adjusting a parameter of the imaging device by using difference information between the first detection projection information and second detection projection information obtained by scanning the calibration phantom with the imaging device, so as to calibrate the imaging device to obtain a calibrated target parameter (S230).

This application relates to the field of medical system coordinate system calibration technology, and provides a calibration phantom and a method for determining the pose of the calibration phantom. It allows for the calibration of image acquisition devices at different installation positions using different sets of calibration surfaces of the calibration phantom, without the need to rearrange the calibration phantom. The calibration phantom provided in this application includes multiple sets of calibration surfaces; within the same set of calibration surfaces, the first calibration surface is perpendicular to the second and third calibration surfaces respectively; the normal of the second calibration surface in the coordinate system of the image acquisition device forms a first angle with the target coordinate axis of the image acquisition device coordinate system; the normal of the third calibration surface in the coordinate system of the image acquisition device forms a second angle with the target coordinate axis; the relationship between the first and second angles is consistent across all sets of calibration surfaces.

This invention relates to a bone mineral density measurement system and method. The system includes a CT scanner with a quantitative computed tomography (QCT) module, an independent single-calibration phantom, and a QCT data image processing program. The devices can exchange data via network or mobile storage. The data receiving module of the QCT data image processing program receives medical digital images from the CT scanner and measures the patient's bone mineral density through the bone mineral density analysis module. This invention combines a CT scanner, QCT, and a single-calibration phantom, employing an asynchronous scanning method that separates the phantom and the patient. This results in higher measurement accuracy, greater convenience, and improved patient comfort.

This application relates to the field of medical imaging technology, and in particular to a method, apparatus, device, system, and medium for geometric calibration of a multi-source multi-detector system. The method includes: determining the coupling relationship between the X-ray source and detector of the multi-source multi-detector system based on the irradiation relationship between the X-ray source and detector; dividing the X-ray source and detector of the multi-source multi-detector system into coupled X-ray source subsets, coupled detector subsets, and uncoupled subsets based on the coupling relationship; designing a calibration phantom based on the design parameters of the multi-source multi-detector system and constructing a calibration dataset; and iteratively solving the geometric parameters of the multi-source multi-detector system sequentially based on the coupled X-ray source subset, coupled detector subset, uncoupled subset, and an objective function constructed using the calibration dataset, to complete the calibration of the overall geometric parameters of the multi-source multi-detector system. This solves the problem of high computational complexity in the geometric parameter calibration of multi-source multi-detector systems in related technologies.

An apparatus and method for calibrating a photon-counting computed tomography (PCCT) apparatus, includes performing for each offset from a rotation center, a scan of a calibration phantom placed at the offset to obtain calibration data including measured count rate data. Location parameters of the calibration phantom are estimated for each of the plurality of offsets, based on the obtained calibration data. Thickness data of the calibration phantom is determined based on the estimated location parameters. A curve is estimated, by curve fitting using the measured count rate data and the determined thickness data, indicating a relationship between the energy bin count rate and phantom thickness, for each energy bin of each pixel of the plurality of pixels. A first look-up table is generated for pixel-to-pixel count rate variation correction, and the first look-up table is applied to acquired energy bin count data to reduce ring artifacts in an image reconstructed using the acquired energy bin count data. A second look-up table is generated for both pixel-to-pixel count rate variation correction and additional count-rate non-linearity correction, using water as the calibration material, and the second look-up table is applied to reduce both ring artifacts and cupping or doming artifacts in an image reconstructed using the acquired energy bin count data.

A method for reducing metal artifacts in CT images, including the following steps: a material decomposition (MD) calibration step, using multiple MD calibration phantoms with known characteristics and multiple spectral CT data corresponding thereto to construct a system characteristic model of spectral CT; and a MD testing step, including: the following steps: imaging multiple testing objects with a different unknown material and thickness to obtain projection-based multiple spectral CT imaging data of different energy bins; obtaining corresponding multiple basis material images of different materials based on projection data according to the spectral CT imaging data and the system characteristic model of spectral CT; and combining the basis material images and a photon energy information to be recombined with each other to obtain multiple virtual monoenergetic images.

The invention provides a PCCT device and a control method thereof, which can improve interpolation precision related to substance discrimination and shorten processing time. This PCCT device is provided with: a scanner that rotates, around a subject, an X-ray source that irradiates X-rays to the subject and a photon counting detector that detects X-rays that have passed through the subject for each of a plurality of energy intervals; and an image generation unit that generates a tomographic image using projection data calculated from the output of the photon counting detector, the PCCT device being characterized by being further provided with: a map creation unit that creates a tomographic image using projection data calculated from the output of the photon counting detector; creating a calibration data map on the basis of the number of X-ray photons transmitted through each of a plurality of calibration phantoms having a first base material and a second base material of known material and thickness; a region division unit that divides the calibration data map into a non-linear region and a linear region; and an interpolation unit that performs a non-linear interpolation in the non-linear region and a linear interpolation in the linear region.

The application discloses a skin dose calculation method based on a depth camera, comprising the following steps: obtaining the transformation relationship between the beam coordinate system of a three-dimensional perspective device and the camera coordinate system of the depth camera by calibrating a calibration phantom with a plurality of marker balls; collecting corresponding images by the depth camera and calculating the coordinates of each pixel point in the image under the beam coordinate system according to the transformation relationship; determining the beam region according to the beam angle of the ray source, combining the coordinates of each pixel point to determine the actual incident position and the incident depth of the patient, and calculating the corresponding skin dose accordingly. The application can locate the actual incident position of the patient by the depth camera, calculate the skin dose at the actual incident position, and display accurate skin dose indication.

A calibration phantom is configured to be difficult to deform and easy to handle. The calibration phantom can be used in a case of acquiring calibration data of a photon-counting type detector that outputs an electrical signal corresponding to photon energy of an incident X-ray. The calibration phantom includes first base substances and a second base substance which are known substances, the second base substance having an atomic number larger than an atomic number of the first base substances and being sandwiched between the first base substances.

The application discloses an absolute quantitative correction method and device of a medical imaging equipment, and relates to the technical field of correction of nuclear medical imaging equipment. In the execution of the method, the actual activity concentration of a calibration phantom injected with a first known tracer activity is taken as a first activity concentration; then the activity concentration of the calibration phantom injected with the first known tracer activity in a first image domain acquired and calculated by the medical imaging equipment is taken as a second activity concentration; and finally, a correction factor is calculated based on the first activity concentration and the second activity concentration, and the correction factor is used for correcting the absolute quantification of the medical imaging equipment. In this way, the correction factor is calculated by comparing the activity concentration calculated by the medical imaging equipment with the actual activity concentration of the calibration phantom, so that the medical imaging equipment can accurately adjust the measurement results according to the correction factor when performing subsequent absolute quantitative analysis, and the effect of improving the absolute quantitative accuracy of the medical imaging equipment is achieved.

To provide a PCCT device capable of improving interpolation precision regarding material discrimination and shortening the processing time, and a control method for the device.SOLUTION: A PCCT device including an X-ray source irradiating a subject with X rays, a scanner turning a photon counting type detector that detects the X-rays passing through the subject for each of a plurality of energy bins around the subject, and an image generator using projection data calculated on the basis of an output of the photon counting type detector to generate a tomographic image is characterized by further having: a map generation unit generating a calibrated data map on the basis of the number of X-ray photons passing through each of a plurality of calibration phantoms having a first base material and a second base material with known materials and thickness; an area division unit dividing the calibrated data map into a non-linear area and a linear area; and an interpolation unit performing non-linear interpolation in the non-linear area and linear interpolation in the linear area.SELECTED DRAWING: Figure 4

The invention provides radiotherapy equipment, a calibration die body and a positioning lamp calibration method. The radiotherapy equipment comprises an annular rack, three positioning lamps and support assemblies in one-to-one correspondence with the positioning lamps. The three sets of support assemblies are arranged in the circumferential direction of the annular rack at intervals, and each positioning lamp is arranged on the corresponding support assembly and is adjustable in posture. The postures of the three positioning lamps meet the condition that one positioning lamp emits a positioning light beam corresponding to the sagittal plane of the human body, and the other two positioning lamps are oppositely arranged and respectively emit two positioning light beams which are perpendicular to each other and correspond to the cross section and the coronal plane of the human body one to one; and positioning light beams emitted by the three positioning lamps are intersected at a set virtual isocenter. According to the radiotherapy equipment, the positioning lamp is directly arranged on the annular rack of the radiotherapy equipment, so that the distance between the positioning lamp and the virtual isocenter is reduced, the moving distance of a user can be reduced in the process of debugging and calibrating the positioning lamp by the user, and the debugging and calibrating efficiency of the positioning lamp is improved.

Disclosed herein is a computer-implemented method for calibrating an imaging apparatus mounted to a rotatable gantry, wherein the imaging apparatus comprises a detector, and a source of imaging radiation configured to emit imaging radiation in a field of view, the emitted imaging radiation having an imaging radiation axis. The method comprises performing a calibration process which comprises obtaining a first projection image of a calibration phantom positioned at a first position within the field of view, determining a projected location of the calibration phantom in the first projection image, and, based on a distance between the determined projected location of the calibration phantom and one or more pixels in the first projection image representing a crossing point between the detector and the imaging radiation axis when the imaging apparatus is in a preferred configuration, determining a relative angle of rotation, α, between the detector and the source of imaging radiation.

To provide a calibration phantom holder which reduces the number of components required for calibration and an installation area, and also reduces the number of user operations of an engineer who performs calibration.SOLUTION: A calibration phantom holder for an imaging system is provided. In an example, the calibration phantom holder comprises a horizontal member comprising a plurality of parallel slots on a top surface of the horizontal member. Each parallel slot of the plurality of parallel slots is configured to support one or more calibration phantoms. The calibration phantom holder includes a vertical member perpendicularly coupled to the horizontal member. The vertical member is configured to couple to a support system of the imaging system.SELECTED DRAWING: Figure 3

The invention discloses a pose calibration method, device and equipment based on Gaussian radiation and a storage medium, and the method comprises the steps: carrying out the image collection of a target calibration motif based on target calibration equipment, and generating a target motif image sequence; and based on a pre-trained Gaussian radiation model, performing image matching on the motif images in the target motif image sequence, and performing pose calibration on the target calibration device at a collection view angle corresponding to the motif image according to an imaging pose, corresponding to the matched motif image, in the Gaussian radiation model. According to the technical scheme, the flexibility and the stability of geometric pose calibration of the calibration equipment are improved.

The invention relates to the technical field of computed tomography, in particular to a tomography imaging method and device, tomography equipment and a storage medium, and aims to realize coordinate system alignment of high-resolution and large-view imaging links in a public reconstruction space through a first projection matrix and a second projection matrix constructed on the basis of the same calibration motif. A geometric consistency basis is provided for joint reconstruction of double-source projection data; a projection matrix is fused into a reconstruction residual error minimization process, iterative reconstruction is carried out in combination with image structure regularization constraint, global geometric consistency and local detail fidelity are both considered under the condition that an external high-resolution label is not needed, and the overall image resolution and imaging quality are improved while the large-view imaging capability is maintained.

The utility model relates to a kind of laser lamp verification mould, including mould main body, level, adjusting support leg and support leg drive assembly, cross mark area is provided on mould main body upper surface and four sides, identification metal ball is provided at the center of mould main body, level is set on mould main body upper surface, four diagonal places of mould main body lower surface are provided with screw hole, adjusting support leg includes support base and rotating column, rotating column lower end is hinged with support base, rotating column outer circumferential surface is provided with external thread, external thread and screw hole are adapted, support leg drive assembly is used to drive support leg to adjust up and down, the abrasion of this mould can be avoided when leveling operation.

The invention provides a PCCT device and a control method thereof. This PCCT device is provided with: a scanner that rotates, around a subject, an X-ray source that irradiates X-rays to the subject and a photon counting detector that detects X-rays that have passed through the subject for each of a plurality of energy intervals; and an image generation unit that generates a tomographic image using projection data calculated from the output of the photon counting detector, the PCCT device being characterized by being further provided with: a map creation unit that creates a tomographic image using projection data calculated from the output of the photon counting detector; creating a calibration data map on the basis of the number of X-ray photons transmitted through each of a plurality of calibration phantoms having a first base material and a second base material of known material and thickness; an expansion unit that creates an expanded data map obtained by expanding the calibration data map to a negative region by performing extrapolation processing on the number of X-ray photons; and a substance discrimination unit that discriminates a substance on the basis of the extended data map.

The present invention relates to a computer-implemented method for phantomless calibration of medical images, comprising: - obtaining medical images without calibration phantoms of a plurality of previous subjects; - obtaining calibration laws for said obtained medical images without calibration phantoms; - training an artificial intelligence algorithm with at least one dataset of those obtained medical images without calibration phantoms and with those calibration laws (each with its respective calibration law), to learn a mathematical estimator that infers from the image data the calibration coefficients of the calibration laws; and - calibrating with the at least one learned mathematical estimator at least one medical image of a current subject acquired without using a calibration phantom. The present invention also relates to a system and a computer program for phantomless calibration of medical images both adapted to implement the method of invention.

The invention relates to material decomposition calibration for an X-ray imaging system. An X-ray imaging system, such as a computed tomography (CT) imaging system, is provided for material decomposition calibration and is intended for use with a calibration phantom. The X-ray imaging system includes an X-ray source configured to emit X-rays and an X-ray detector arranged in an X-ray beam path configured to generate detector data. The calibration phantom is located in the X-ray beam path. The X-ray imaging system also includes an X-ray beam confinement device comprising at least one calibration element in the X-ray beam path. The X-ray imaging system also includes image processing circuitry configured to acquire projection data for a set of projections based on the detector data, and determining a path length through the at least one material of the at least one calibration element and the at least one material of the calibration phantom based at least in part on the acquired projection data for performing a material decomposition calibration.