摘要:
A medical imaging device has an emission tomograph, at least one ultrasonic (US) probe for providing images giving real-time information about the location of the internal organs of a subject, a tracking system for spatially locating the at least one ultrasonic probe in relation to the medical imaging device, and an image processing unit in which the location information obtained by the ultrasonic probe is used for attenuation correction of image information obtained by the emission tomograph.
摘要:
Apparatus and methods for simulating a sheet source with a line source for determining normalization coefficients for the detectors in positron emission tomography (PET) scanners and single photon emission computed tomography (SPECT) scanners. A line source, oriented perpendicular to the axis of a scanner gantry, is moved along the axis while the detectors are stationary and positioned substantially parallel to the plane in which the source moves. In another embodiment, an axially mounted line source moves parallel to a diameter of the gantry while the stationary detectors are positioned substantially parallel to the plane in which the source moves. In still another embodiment, the line source is stationary and positioned parallel to the gantry axis and off center while the detectors move relative to the line source. A shaped attenuator is placed around the source in this last embodiment.
摘要:
A normalization apparatus and method for a PET scanner with panel detectors for obtaining an estimate of a normalization array, for correction for count rate effects on the normalization array, and for measurement of the relation between the normalization array and the count rate. The method of the present invention is based on two quasi-independent radial and axial components, which are count rate dependent due to sensitivity changes across the detector blocks. A scatter source is disposed at the center of the FOV and a scatter-free source is disposed at the outer edge of the FOV. The method computes the normalization array through several steps which evaluate the geometric profile, the axial profile, and the correction factor. A count rate correction is introduced to extend the normalization array to any count rate.
摘要:
A medical imaging device has an emission tomograph, at least one ultrasonic (US) probe for providing images giving real-time information about the location of the internal organs of a subject, a tracking system for spatially locating the at least one ultrasonic probe in relation to the medical imaging device, and an image processing unit in which the location information obtained by the ultrasonic probe is used for attenuation correction of image information obtained by the emission tomograph.
摘要:
A transmission source serves to detect activity from a radiation source for correcting attenuation in either PET mode or SPECT mode. The transmission source includes a detector dedicated to collecting attenuation data in PET mode. A collimated radiation source and a detector are positioned with respect to a tomography device such that only a selected strip of the imaging detector of the tomograph is illuminated such that events unrelated to the attenuation are eliminated. The transmission source can either be a coincidence transmission source or a singles transmission source and includes a collimator in which is disposed a radiation source. An opening is defined by the collimator for exposing a selected portion of the imaging detectors of the tomograph device. Positioned behind the radiation source, relative to the imaging detectors, is the dedicated attenuation detector. In a dual head tomograph device, one transmission source of the present invention is disposed opposite each bank of imaging detectors. The sources and the associated collimators are positioned to the side of each head at a slight angle relative to the respective head. The sources and detectors are fixed relative to the imaging heads. In order to obtain full coverage of the field of view (FOV) in the same manner as for an emission scan, the heads and sources are rotated about the center of the camera. In SPECT mode, the point source is selected to have sufficiently high energy to shine through the patient and the collimators associated with the imaging detector.
摘要:
A system for dual-mode medical imaging is provided. The system features components for PET imaging as well as for ultrasonic imaging, with an internal probe that has components to provide capability for both. The system provides cost-efficient PET imaging for smaller regions and organs of interest than conventional full body PET scanner apparatus.
摘要:
An articulating detector array for gamma cameras is disclosed which is adaptable to perform different imaging techniques in a single apparatus. The articulating detector array is adapted to detect incident gamma radiation from diverse directions as well as Compton scattering thereof without the need of a collimator, as so has improved gamma ray detection efficiency. The detector array includes radiation detectors in an array and movable to a plurality of positions, in which each radiation detector is responsive to gamma radiation from a target for generating detection signals for use in tomographic imaging of the source. The detector array includes articulating support structures for mounting the detectors to the base and for moving the detectors from a first position to a second position. In one embodiment, the articulating support structures includes a first portion connected to a detector; and a second portion connected to the base, in which the first portion is adapted to extend from the second portion from the first position to the second position. In another embodiment, the articulating support structures include a pivot for pivotably mounting the detectors and for rotating the detectors from a first position to a second position.
摘要:
A constraint having a main body and at least one coupler. The main body can be substantially arcuate in shape and can be configured to constrain a patient. The at least one coupler can couple the main body to a bed or treatment pallet. The constraint can be sized to restrict a patient within a computerized tomography (CT) scan field of view.
摘要:
A method of reducing ring artifacts in tomographic images including providing an original digitized projection measurement comprising a plurality of intensities corresponding to a domain of points on an 2-dimensional grid, operating on said original projection measurement with a filter wherein features of high radial frequency and low angular frequency are attenuated, forming a weighted mixture of said filtered projection measurement and said original projection measurement wherein ring artifacts in said original tomographic image are substantially reduced, and reconstructing the projection measurement to form a tomographic image. Alternatively, a first tomographic image is reconstructed from said original projection measurement, a second tomographic image is reconstructed from said filtered projection measurement, and a weighted mixture is formed from said first tomographic image and said second tomographic image.
摘要:
A method of reducing ring artifacts in tomographic images including providing an original digitized projection measurement comprising a plurality of intensities corresponding to a domain of points on an 2-dimensional grid, operating on said original projection measurement with a filter wherein features of high radial frequency and low angular frequency are attenuated, forming a weighted mixture of said filtered projection measurement and said original projection measurement wherein ring artifacts in said original tomographic image are substantially reduced, and reconstructing the projection measurement to form a tomographic image. Alternatively, a first tomographic image is reconstructed from said original projection measurement, a second tomographic image is reconstructed from said filtered projection measurement, and a weighted mixture is formed from said first tomographic image and said second tomographic image.