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 coincidence transmission source serves to detect coincident activity from a radiation source. The coincidence transmission source includes a detector dedicated to collecting attenuation data. 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 coincidence transmission source 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. The attenuation detector and collimator are designed to illuminate only a strip of the imaging detector, thereby eliminating events not of interest in the attenuation measurement. In a dual head tomograph device, one coincidence 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.
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 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 Cerium-Doped Lutetium Oxyorthosilicate scintillator boule having a graded decay time. The method for manufacturing an LSO:Ce crystal boule having a decay time gradient decreasing from the top end to the bottom end first includes the step selecting an iridium crucible. The crucible is selected based upon its diameter relative to the diameter defined by said crystal boule. The crucible is also selected based upon its volume relative to the volume of the crystal boule to be grown. A Cerium dopant (CeO2) is added to a mixture of Lutetium Oxide (Lu2O3) and Silicon Dioxide (SiO2). The composition is heated until melted to define a melt. A seed crystal is then placed in contact with the melt, is rotated, and slowly withdrawn, thereby yielding an LSO:Ce crystal boule defining a decay time gradient.
摘要:
A two-dimensional photon position encoder system (10) and process which includes a detector (20) for enhancing the spatial resolution of the situs of the origin of incident photons of gamma rays. A plurality of scintillator material members (22) interact with the incident photons and produce a quantifiable number of photons which exit the scintillation material members. A tuned light guide (68) having a plurality of radiation barriers (92) of predetermined lengths define slots which are operatively associated with one of the scintillator material members. These slots (90) serve to enhance the predictability of the statistical distribution of photons along the length of the slotted light guide (68). A detector (20) detects the distribution of the photons at preselected locations along the length of the slotted light guide. In one embodiment, this detector (20) comprises a photomultiplier (70) which gathers information concerning the photoelectrons which are then counted. The statistical distribution of these photoelectrons is processed by an improved pattern recognition technique such that the positioning information can be determined.
摘要:
A scintillation detector which includes a plurality of discrete scintillators composed of one or more scintillator materials. The discrete scintillators interact with incident radiation to produce a quantifiable number of photons with characteristic emission wavelength and decay time. A light guide is operatively associated with the scintillation crystals and may be either active or non-active and segmented or non-segmented depending upon the embodiment of the design. Photodetectors are provided to sense and quantify the scintillation light emissions. The process and system embodying various features of the present invention can be utilized in various applications such as SPECT, PET imaging and simultaneous PET systems. In accordance with the present invention, the detector array of the present invention incorporates either a single scintillator layer of discrete scintillators or discrete scintillators composed of two stacked different layers that can be the same scintillator material or of two different scintillator materials. In either case the different layers are composed of materials that have distinctly different decay times. The variants in these figures are the types of optical detectors which are used, i.e. photomultipliers and/or photodiodes, whether or not a segmented optical light guide is used, and whether the light guide is active or non-active. If a segmented optical light guide is used then the variant is whether the configuration is inverted or non-inverted.
摘要:
A two dimensional photon position encoder system (10) and process which includes a detector (20) for enhancing the spatial resolution of the situs of the origin of incident photons of gamma rays. A plurality of scintillator material members (22) interact with the incident photons and produce a quantifiable number of photons which exit the scintillation material members. A tuned light guide (68) having a plurality of radiation barriers (92) of predetermined lengths define slots which are operatively associated with one of the scintillator material members. Photons exiting the scintillator material members (22) enter an operatively associated slot in said slotted light guide. These slots (90) serve to enhance the predictability of the statistical distribution of photons along the length of the slotted light guide (68). A detector (20) detects the distribution of the photons at preselected locations along the length of the slotted light guide. In one embodiment, this detector (20) comprises a photomultiplier (70) which gathers information concerning the photoelectrons which are then counted. The statistical distribution of these photoelectrons is processed by an improved pattern recognition technique such that the positioning information can be determined.