摘要:
Point spread function (PSF) radial filtering in a line of response space. Modeling a radial component, R, of a point spread filter as a function of at least a radial projection index ρ, a radial image space coordinate r, and an azimuth θ. The index ρ is characterized by an asymmetrical Gaussian distribution having where σleft(r) and σright(r) derived from point source measurements, and an adjustment σJ(r, θ) estimated from point source sinogram by Josephs' projector.
摘要:
A method of TOF-PET image reconstruction using time-truncated TOF-PET projection data. The time-truncated TOF-PET data is obtained by narrowing the scanner time window to a smaller “time window field of view,” which reduces the field of view of a TOF-PET scanner. This results in a lower list mode stream transfer rate, which can be useful in high count rate data acquisitions, in particular 82Rb cardiac studies.
摘要:
A constant fraction discriminating circuit outputs timing information corresponding to an event corresponding to a detected photon for providing nuclear medicine imaging. The constant fraction discriminating circuit includes a stripline or microstrip delay element.
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 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.
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.
摘要:
Normalization coefficients in are computed for positron emission tomography (PET) continuous bed motion acquisition (CBM). The normalization coefficients for the lines-of-response in CBM account for the change in decay of the injected isotope over time and/or changes in velocity of the bed motion.
摘要:
Point spread function (PSF) radial filtering in a line of response space. Modeling a radial component, R, of a point spread filter as a function of at least a radial projection index ρ, a radial image space coordinate r, and an azimuth θ. The index ρ is characterized by an asymmetrical Gaussian distribution having where σleft(r) and σright(r) derived from point source measurements, and an adjustment σJ(r, θ) estimated from point source sinogram by Josephs' projector.
摘要:
A method for processing an image which has the steps of a) receiving acquired data necessary to obtain an image and estimating a preliminary image; b) selecting at least one image element within the image; c) performing an iterative algorithm for processing the image at least on the at least one image element; d) computing a difference between the processed at least one image element and the at least one image element; and e) repeating the steps c) and d) until the difference is below a predefined threshold.