University of Washington

Thomas K Lewellen

Robert S Miyaoka

Lawrence R MacDonald

Scott Hauck

William C J Hunter

Michael Haselman

Paul Eugene Kinahan

Adam Alessio

Jacques Christophe Rudell

Kyle Morgan Champley

Hubert J Vesselle

Samrat Dey

An input driven self-clocked dynamic comparator, and associated systems and methods are described herein. In one embodiment, self-clocked dynamic comparator, includes a latch configured to receive an input voltage (VIN), a reference voltage (VREF) and a clocking (CLKsf) signal, and configured to output a first rail-to-rail output (OUT+) signal and a second rail-to-rail output (OUT−) signal. The self-clocked dynamic comparator also includes a pre-amplifier (PRE-AMP) configured to output an enable (TRI) signal based on a comparison between the VIN and an adjusted VREF. The self-clocked dynamic comparator further includes a pre-amplifier (PRE-AMP) configured to output an enable (TRI) signal based on a comparison between the VIN and an adjusted VREF, and a logic gate configured to receive the TRI signal and one of the OUT+ signal and OUT− signal, and configured to output the CLKsf signal. The cycles of the CLKsf signal cause the latch to dissipate energy.

Input driven self-clocked dynamic comparator

A radiation detector is disclosed that includes a scintillation crystal and a plurality of photodetectors positioned to detect low-energy scintillation photons generated within the scintillation crystal. The scintillation crystals are processed using subsurface laser engraving to generate point-like defects within the crystal to alter the path of the scintillation photons. In one embodiment, the defects define a plurality of boundaries within a monolithic crystal to delineate individual detector elements. In another embodiment, the defects define a depth-of-interaction boundary that varies longitudinally to vary the amount of light shared by neighboring portions of the crystal. In another embodiment the defects are evenly distributed to reduce the lateral spread of light from a scintillation event. Two or more of these different aspects may be combined in a single scintillation crystal. Additionally, or alternatively, similar SSLE defects may be produced in other light-guiding elements of the radiation detector.

Optical-interface patterning for radiation detector crystals

A method for estimating a line or response in a positron emission tomography scanner having depth of interaction estimation capability. The method utilizes information from both detector modules detecting a coincident event. A joint probability density function combining factors accounting for intermediate Compton scattering interactions and/or a final interaction that may be either a Compton scattering interaction or photoelectric absorption is calculated. In a preferred embodiment, a Bayesian estimation scheme is used to integrate the PDF for all permutations of the measured signal pairs, and the permutation with the largest joint probability is selected to construct the estimated line of response.

Line of response estimation for high-resolution PET detector

Improved processing electronic hardware are disclosed that facilitate the efficient processing of PET system data, while enhancing accuracy and compatibility of PET systems with other analytical methods (e.g., magnetic resonance imaging). Improvements include the use of an application-specific integrated circuit (ASIC) for summing, by row, column, and diagonal, the output signals from an array of photodetectors in the PET system.

Data-processing electronics for use in a positron-emission tomography system

A method for estimating the start time of an electronic pulse generated in response to a detected event, for example the start time for pulses received in response to photon detection in positron emission tomography, includes providing a detector that detects an external event and generates an electronic analog pulse signal. A composite reference pulse curve is calculated to represent analog pulse signals generated by the detector. Upon receiving an analog pulse signal, it may be filtered, and then digitized, and normalized based on the area of the digital signal. Using at least one point of the normalized digital pulse signal, the composite reference pulse curve shape is used to estimate the pulse start time.

Data acquisition for positron emission tomography

A method for estimating the start time of an electronic pulse generated in response to a detected event, for example the start time for pulses received in response to photon detection in positron emission tomography, includes providing a detector that detects an external event and generates an electronic analog pulse signal. A parameterized ideal curve shape is selected to represent analog pulse signals generated by the detector. Upon receiving an analog pulse signal, it may be filtered, and then digitized, and normalized based on the area of the digital signal. Using at least one point of the normalized digital pulse signal, a curve from the parameterized ideal curve shape is selected, that best represents the received analog pulse signal, and the selected curve is used to estimate the pulse start time.

A method is disclosed for obtaining linear attenuation coefficients for interpreting a PET scan of a region. The method is suitable for use when high molecular weight materials are present in the region, such as contrast agents or metal objects. The method includes obtaining first and second x-ray CT data sets of the region of interest at two different energies or voltage potentials and differencing corresponding CT numbers. The difference values are used to distinguish portions of the region that are bone from portions of the region that are contrast agent or other high molecular weight material. The obtained CT data set is then used to obtain an attenuation coefficient map of the region at the PET energy of 511 keV, for example, using a linear scaling factor suited to the particular identified material. Difference values at or near zero may be used to identify soft tissue portions of the region.

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Port Ludlow, WA, United States of America

Thomas K Lewellen