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:
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:
Apparatuses and methods are provided that minimize the effects of dark-current pulses. For example, in one embodiment of the invention, a method is provided where a first pixel is struck (i.e., a primary pixel). Pixels struck within a fixed time frame after the primary pixel is struck are referred to as secondary pixels. After a short fixed time frame has expired, the number of primary and secondary pixels is added. If the count exceeds a threshold, the primary pixel was activated by the first (or early) photon from a true gamma event. If the threshold is not met then it is likely the primary pixel generated a dark pulse that should be ignored.
摘要:
A representative positron emission tomography (PET) calibration system includes a PET scanner having a ring detector, a phantom that is placed at approximately the center of the ring detector, and a time alignment calibration manager that is coupled to the PET scanner. The time alignment calibration manager detects coincidence events from the phantom, calculates position of time of flight events from the ring detector based on the detected coincidence events, and calculates time offsets for the ring detector using a mean value calculation based on the calculated position of the time of flight events.
摘要:
A method for correcting PET emission data for prompt gamma emission background components present in non-pure positron-emitting isotopes uses a two component fit of modeled scatter and modeled prompt gamma emission in the area of scatter tails in a normalized emission sinogram. The method allows a PET scan using non-standard PET isotopes to be quantitative and thus more clinically useful.
摘要:
A method for determining quality of sinograms produced by a medical imaging device. The method may include placing a uniform phantom object in the field of view of the medical imaging device; acquiring one or more phantom sinograms of the uniform phantom object; establish a set of parameters for the acquired one or more phantom sinograms; and determine, based on pre-set ranges of the parameters, the quality of sinograms produced by the medical imaging device. The parameters may be one or more parameters of a group of parameters consisting of block uniformity, block efficiency, randoms rate, scanner efficiency, and scatter ratio.
摘要:
A method for improving clinical data quality in Positron Emission Tomography (PET). The method provides for the processing of PET data to accurately and efficiently determine a data single-to-noise ratio (SNR) corresponding to each individual clinical patient scan, as a function of a singles rate in a PET scanner. The method relates an injected dose to the singles rate to determine SNR(Dinj), and provides an accurate estimate of a quantity proportional to SNR, similar in function to the SNR(Dinj). Knowledge of SNR(Dinj) permits determination of peak SNR, optimal dose, SNR deficit, dose deficit, and differential dose benefit. The patient dose is fractionated, with a small calibration dose given initially. After a short uptake, the patient is pre-scanned to determine T, S, and R. An optimal does is then determined and the remainder injected.
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 method for improving clinical data quality in Positron Emission Tomography (PET). The method provides for the processing of PET data to accurately and efficiently determine a data signal-to-noise ratio (SNR) corresponding to each individual clinical patient scan, as a function of a singles rate in a PET scanner. The method relates an injected dose to the singles rate to determine SNR(Dinj), and provides an accurate estimate of a quantity proportional to SNR, similar in function to the SNR(Dinj). Knowledge of SNR(Dinj) permits determination of peak SNR, optimal dose, SNR deficit, dose deficit, and differential dose benefit. The patient dose is fractionated, with a small calibration dose given initially. After a short uptake, the patient is pre-scanned to determine T, S, and R. An optimal dose is then determined and the remainder injected.
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.