307 results about "Scattering correction" patented technology

An X-ray CT apparatus includes a plurality of X-ray irradiation sources and a plurality of X-ray detection units. Timing of irradiation of X-ray is shifted by each X-ray irradiation source, the detection unit separately obtains projection data and scatter correction data. In a scatter correction unit, scatter correction is performed based on the projection data and the scatter correction data.

A general imaging scheme is proposed for applications of CBCT. The approach provides a superior CBCT image quality by effective scatter correction and noise reduction. Specifically, in its implementation of CBCT imaging for radiation therapy, the proposed approach achieves an accurate patient setup using a partially blocked CBCT with a significantly reduced radiation dose. The image quality improvement due to the proposed scatter correction and noise reduction also makes CBCT-based dose calculation a viable solution to adaptive treatment planning.

Described herein are improved methods for correcting cone beam computed tomography signals to reduce scatter contamination contained therein. Generally, the improved methods involve generating a plurality of two-dimensional projection images of a subject from a three-dimensional multi-detector computed tomography image of the subject. This is followed by subtracting the plurality of two-dimensional projection images from a plurality of two-dimensional cone beam projection images of the subject to produce a plurality of two-dimensional estimated error projections that comprise an estimated error in the plurality of two-dimensional cone beam projection images. The plurality of two-dimensional estimated error projection images are subtracted from the plurality of two-dimensional cone beam projection images to generate a plurality of two-dimensional corrected cone beam projection images. A three-dimensional corrected cone beam computed tomography image of the subject is then constructed from the plurality of two-dimensional corrected cone beam projection images.

The invention discloses a scattering determination and corrector method of a taper bunch CT system. After arranging a parameter, an air projected picture and a beam attenuation grid projected picture are collected. A circular scanning is carried out on the detected object. A projected picture set I of the detected object with beam attenuation grid and a projected picture set II of the detected object are collected. The projected attitude of the center of each metal ball in the beam attenuation grid is calculated. A scattered field distributing image corresponding to the projected picture of the projected picture set I is calculated through a beam attenuation grid corrector method. A projected picture set III after scattering correction is gained through the projected picture set I subtracting the corresponding scattered field distributing image. Thereby, a sequence slice image after scattering correction is reconstructed through a filter back-projection reconstruction method. The invention can be applied to the scattering correction of the taper bunch CT system from low energy to medium or high energy. The invention is a simple and effective scattering correction method of the taper bunch CT system.

Embodiments of methods and/or apparatus for 3-D volume image reconstruction of a subject, executed at least in part on a computer for use with a digital radiographic apparatus, can obtain image data for 2-D projection images over a range of scan angles. For each of the plurality of projection images, an enhanced projection image can be generated. In one embodiment, a first scatter intensity distribution through the plurality of projection images can be modulated based on a first scaling function and a SPR to generate a second scatter intensity distribution through the plurality of projection images, which can be combined with the original plurality of projection images.

Methods and systems for providing scatter correction in a positron emission tomography (PET) system are provided. The method includes determining a look-up table of scatter sinograms during a PET acquisition scan period. The method further includes scatter correcting acquired scan data obtained during the PET acquisition scan period.

An image processing apparatus includes a scatter simulation processor which processes measured sinograms generated from imaging data acquired for an imaging subject by an imaging apparatus to produce a scatter sinogram that represents a shape of scatter contribution. A scatter scaling processor utilizesa Monte Carlo simulation to determine a scatter fraction and scales the scatter sinogram to generate a scaled scatter sinogram that matches the scatter contribution in the measured sinogram. A reconstruction processor reconstructs the imaging data into an image representation using the scaled scatter sinogram for scatter correction.

A CT scanner with scatter correction device and a method for scatter correction are provided. The method of correcting CT images from artifacts caused by scattered radiation comprises affixing to the non-rotating frame of the CT gantry a plurality of shields for shielding some of the CT detector elements from direct X ray radiation, while allowing scattered radiation to arrive at said shielded elements; measuring scatter signals from said shielded elements, indicative of scattered radiation intensity; and correcting for scatter by subtracting scatter intensity values estimated from said measured scatter signals from signals measured by unshielded detector elements.

The present approach relates to the use of machine-learning in convolution kernel design for scatter correction. In one aspect, a neural network is trained to replace or improve the convolution kernel used for scatter correction. The training data set may be generated probabilistically so that actual measurements are not employed.

The invention discloses a device and a method for detecting biological tissue of pressure modulation near infrared spectrum. Biological tissue physiological status judgment and volume difference spectrum measurement are achieved according to pressure and spectrum measuring results in the process of deformation of the biological tissue: changing of biological tissue diffuse reflection spectrum along with the pressure and action time is respectively measured, multiplicative scatter correction and second derivative processing are conducted to the measured spectrum, content change of free water and bound water is obtained, fitting processing is conducted to the content change of the free water and the bound water, the pressure and the action time, biological tissue status is judged according to a fitting curve trend; differential treatment is conducted to diffuse reflection spectrum obtained under different pressure values, the water content change in the tissue is taken as a reference, physiological background of the tissue is deducted, and spectrum net analyte signals of tissue elements are obtained. According to method for detecting the biological tissue of the pressure modulation near infrared spectrum, rapid detecting of physiological status of the biological tissue is achieved, and spectrum detection accuracy of the tissue elements is improved.

A method, system, and machine readable media are provided for correcting scatter in an image. The method comprises sequentially emitting radiation from a subset of radiation sources toward a detector array and measuring radiation on areas of the detector array not exposed to the emitted primary radiation at the time of measurement. Scatter is estimated from the measured radiation. Furthermore, the scatter estimates are subtracted from the measured data and images with improved image quality are reconstructed.

The invention discloses a convolution-based X-ray CT system beam hardening correction method, belonging to the applying field of industrial CT systems. The method comprises the following steps of: I. conducting scattering correction by clinging an aluminum foil filter plate to a rear collimator; II. setting the scanning parameter of a CT system; III. collecting the background value of the system with a ray source not opening; IV. opening the ray source, and scanning the air in the current laboratory to obtain the ray strength of the current air; V. scanning a group of standard parts, and collecting the projection data under different thicknesses; VI. fitting a curve to obtain a hardening model and a convolution correction model; VII. conducting hardening correction by utilizing the function of the convolution correction model to obtain the corrected ray strength data; and VIII. conducting image reconstruction by using the corrected ray strength data. With the correction method, the beam hardening correction effect is obvious, the edge of a detected object can be well maintained, the detail part of the detected object can be saved, and the high-precision detection need can be met.

The present invention relates to a method for scattered radiation correction of a CT system, including at least two focus/detector systems operated angularly offset from one another, is disclosed. In the method, at at least one phantom, similar to the examined object at least in a subregion, for at least one of the focus/detector systems, the scattered radiation intensity occurring is determined in the detector of a focus/detector system during the operation of the at least one focus of at least one other focus/detector system. Further, the spatial distribution thereof is stored for a number of angles of rotation of the focus/detector systems. During scanning of the object, the scattered radiation intensities, determined with the aid of a similar phantom that originate from the at least one other focus/detector system, are subtracted from the measured intensities of the first focus/detector system while taking account of the spatial orientation of the focus/detector systems and the beam respectively considered. Finally, absorption values are calculated with the aid of the intensity values thus corrected, and CT pictures or CT volume data are thereby reconstructed.

An X-ray imaging apparatus may include an image acquirer configured to acquire a plurality of X-ray images of an object in different energy bands; and an image processor configured to perform scattering correction on the plurality of X-ray images to remove X-ray scattering from the plurality of X-ray images, perform material separation on the plurality of X-ray images on which the scattering correction has been performed to acquire material information of at least one material included in the object, and repeatedly perform the scattering correction and the material separation depending on whether a predetermined condition is satisfied.

A scatter correction device for radiative tomographic scanners is disclosed. The device comprises at least one steady support component and multiple beam stoppers made of high Z materials such as lead and wolfram. Each beam stopper has two ends fixed on the steady support component respectively. Theses beam stoppers can thus be sustained at fixed locations by the steady support component. During scanning an object, the device is placed between the object and detectors. But when the scatter correction device is applied to a CT scanner, the device is placed between object and radiation source. It attenuates part of the primary radiation with very small affects on the scattered radiation.

The method calculates a scatter estimate for annihilation photons in a subject having a distribution of attenuation. The method can be used for scatter correction of detection data from a positron emission tomographic scanner. The method uses the following steps: —select a first scatter point S₁ and a second scatter point S₂, —determine a first scatter probability for scattering of a photon at scatter point S₁ and a second scatter probability for scattering of a photon at scatter point S₂, —determine an integral of the attenuation over a line connecting S₁ and S₂, —multiply the integral and the scatter probabilities and use the product in the calculation of the scatter estimate.

The invention discloses an offline dose verification method based on improved CBCT (cone beam computed tomography) images. The offline dose verification method includes: subjecting the CBCT images of an individual patient to scatter correction on the basis of Monte-Carlo simulation to acquire a first CBCT image; rectifying the first CBCT image with a planned CT (computed tomography) image to acquire target-region deformation field information; verifying outline information of the planned CD image according to the target-region deformation field information, transplanting the verified outline information to the CBCT images to acquire a second CBCT image; establishing HU-ED calibration curves of the CBCT images according to average HU value of a particular tissue area of the individual patient in the second CBCT image and ED value of a particular tissue area of the planned CT image; performing dose calculation and planned validation on the basis of the second CBCT image, the HU-ED calibration curves, the planned CT and standard CT-ED calibration curves. By the technical scheme, treatment time and cost of the patient can be saved, and accurate adaptive radiation therapy and individual radiation therapy are realized.

The invention discloses a full-spectrum transmission plant biochemical parameter nondestructive detection device and a full-spectrum transmission plant biochemical parameter nondestructive detection method, which are used for solving the technical problems of low model applicability, poor anti-jamming capacity, low detection accuracy, less detected parameters and the like in the conventional spectrum nondestructive detection method. The full-spectrum transmission measurement principle is adopted and a plurality of parameters are simultaneously measured in high accuracy; the time-divided double optical path reference measurement principle is adopted to ensure the accuracy of transmittance spectrum signals; the integrated transmission fixture and program controlled adjustable voltage-stabilizing drive light source circuit makes the measurement principle realized in plant leaf transmittance spectrum measurement so as to form the miniature and portable plant biochemical parameter nondestructive detection device; and in a prediction model of the device, an improved expansion multiple scattering correction method is adopted to correct basic lines of leaves due to scattering and optical path length difference due to different leaf thicknesses, the sensitivity of spectrum data to chemical substance concentration is improved, and the anti-jamming capacity of the model is improved.