Toshiba Medical Systems Corporation

Kabushiki Kaisha Toshiba

Gin-Chung Wang

Kent C Burr

Daniel Gagnon

Yu Zou

Gregory John Mann

Huini Du

Xiaoli Li

Adam Petschke

Jerry Wang

John S Jedrzejewski

A method and apparatus is provided to decompose spectral computed tomography (CT) projection data into material components using singles-counts and total-counts projection data. The singles-counts projection data more accurately solves the material decomposition problem, but can produce multiple results only one of which is correct. The total-counts projection data generates a unique result, but is less precise. The total-counts projection data is used to disambiguate the multiple results of the singles-counts projection data providing a unique results that is also precise. The unique and precise material decomposition can be achieved by limiting a search region for the singles-counts result to a neighborhood surrounding the total-counts result, choosing a singles-counts result that is closest to the total-counts result, choosing a singles-counts result that minimizes a total-counts cost function, or using a combined cost function that includes a singles-counts projection data and energy-integrated projection data.

Apparatus and method for material decomposition of spectrally resolved projection data using singles counts

An apparatus is provided that includes a digital processing circuit to obtain a digital signal corresponding to an output signal of a photon-counting detector; determine, from the obtained digital signal, a plurality of X-ray photons received by the photon-counting detector during a measurement period; determine a corresponding energy level of each of the plurality of X-ray photons; determine, based on the corresponding energy level, a corresponding weight for each of the plurality of X-ray photons; and calculate a sum of the corresponding weights of the plurality of X-ray photons.

Energy-weighted single-binning for a photon-counting detector

A process and device for generating a prototype waveform and a weighting function. The process including obtaining waveforms generated by a detector having at least one photosensor, generating an initial estimate for the prototype waveform and the weighting function and parameterizing the prototype waveform and the weighting function and determining for each waveform an optimal amplitude and an optimal time offset of the prototype waveform. Included are steps of pairing waveforms based on the determined time offsets of the waveforms, calculating an arrival time difference for each pair of waveforms and determining a timing resolution value based on the calculated arrival time differences, determining whether the timing resolution value meets predetermined minimization criteria, and updating the set of parameters for the prototype waveform and the weighting function and repeating the determining, pairing, calculating, and determining, when the timing resolution value fails to meet the predetermined minimization criteria.

Method for timing-pick-off of undersampled pulses from radiation detectors using a photosensor-based radiation detection system applying a prototype waveform and a weighting function

Systems, devices, processes, and algorithms for adapting and/or adjusting a reflectivity of a reflector in a radiation detector. The reflectivity can be changed by a reflectivity control signal that is generated based on an estimated count rate of events so as to adjust a probability of a photosensor detecting light resulting from the event via, for example, a scintillation event. By adjusting the probability, an energy resolution of the radiation detector can be optimized. The reflectivity of a reflector can be changed by changing a state of a thin film, a liquid crystal layer, or a suspended magnetic particle layer.

Reflector having adaptive reflectivity for radiation detection

A method and electronic device for outputting time values and energy of an analog input signal by dynamically determining a plurality of threshold values, comparing, using a plurality of comparator circuits, the plurality of threshold values against the analog input signal, outputting, using at least one time to digital conversion circuit connected to each of the plurality of comparator circuits, a plurality of time values, each time value output when the analog input signal meets or exceeds a threshold value of the threshold values, filtering the analog input signal, performing, using an analog-to-digital conversion circuit, analog-to-digital conversion of the filtered analog input signal to generate a digital signal, and calculating, in response to receiving a trigger signal, an energy of the digital signal.

Apparatus for analog-to-digital conversion with a high effective-sample-rate on the leading edge of a signal pulse

A method and system for calibrating an imaging system in which a positron-emitting radioisotope source is arranged in or adjacent to an imaging region of the imaging system, an annihilation target is arranged at a position separated from the positron-emitting radioisotope source by a predetermined distance, coincident event pairs resulting from annihilation of positrons at the annihilation target are detected, a calibration time offset for a detector element in the imaging system is calculated based on the detected coincident event pairs, and the detector element is calibrated with the completed calibration time offset.

Timing calibration for time-of-flight (TOF) PET using positron-emitting isotopes and annihilation targets

A system and method for processing an analog signal output by a sensor. The system and method converting, using at least one analog-to-digital converter (ADC), the analog output signal to a digital signal, the digital signal including a plurality of samples at a predetermined resolution, detecting whether a trigger condition is met by analyzing the digital signal, detecting an event based on trigger information from the detecting whether a trigger condition is met, generating event information having time information included therein when the event is detected, defining one or more time windows based on the time information included in the event information, performing decimation on the digital signal based on the defined one or more time windows to generate a decimated signal, and outputting the decimated signal.

Apparatus for detection of a leading edge of a photo sensor output signal

Systems, devices, processes, and algorithms for adaptively filtering a signal output from a radiation detector and adaptively sampling the signal. A count rate of events detected by the radiation detector is estimated by a processing unit. An RC time constant of the filter and a sampling rate of an analog-to-digital converter are adjusted based on the estimated count rate. Events are continuously detected by the radiation detector and counted by the processing unit while the adjustable parameters (the RC time constant and the sampling rate) of the filter and the analog-to-digital converter are adjusted on the fly (in real time) to optimize an energy resolution of the detected events, while reducing degradation due to pile-up effects and improving efficiency of the analog-to-digital converter. The filter can be implemented through analog filters, digital filters, or a combination thereof.

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Grayslake, IL, United States of America

Gin-Chung Wang