Analog time adjustment for coincidence detection electronics
First Claim
1. A method to be used with a PET scanner which includes a plurality of detector units, each detector unit including a detection surface area, when a photon impacts a detection surface area at a detection point and an event time, the scanner generating an event detection pulse (EDP), scanner hardware which processes impacting photons causing varying delays between event times and corresponding EDPs, the detector delay corresponding to each detector unit varying as a function of detection point, the method for modifying the EDPs so that the timing of each EDP is essentially temporally accurate relative to all other EDPs, the method comprising the steps of:
- for each EDP;
identifying the detection point;
selecting a compensation factor as a function of the detection point and the generating detector; and
modifying the EDP as a function of the compensation factor.
1 Assignment
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Accused Products
Abstract
A method for correcting the temporal relationships between event detection pulses generated by a PET scanner system, the method including, for each pulse, identifying the impact point of an associated photon on a scanner surface area and based on the impact point, selecting a compensation delay for the pulse and delaying the pulse by the compensation delay. The invention also includes an apparatus for practicing the method.
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Citations
22 Claims
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1. A method to be used with a PET scanner which includes a plurality of detector units, each detector unit including a detection surface area, when a photon impacts a detection surface area at a detection point and an event time, the scanner generating an event detection pulse (EDP), scanner hardware which processes impacting photons causing varying delays between event times and corresponding EDPs, the detector delay corresponding to each detector unit varying as a function of detection point, the method for modifying the EDPs so that the timing of each EDP is essentially temporally accurate relative to all other EDPs, the method comprising the steps of:
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for each EDP;
identifying the detection point;
selecting a compensation factor as a function of the detection point and the generating detector; and
modifying the EDP as a function of the compensation factor. - View Dependent Claims (2, 3, 4, 5)
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6. An apparatus to be used with a PET scanner which includes processing circuitry and a plurality of detector units which, each detector unit including a detection surface area, when a photon impacts a detection surface area at a detection point and an event time, the scanner generating an event detection pulse (EDP), a scanner hardware which processes impacting photons causing varying delays between event times and corresponding EDPs, the detector delay corresponding to each detector unit varying as a function of detection point, the apparatus for modifying the EDPs so that the timing of each EDP is essentially temporally accurate relative to all other EDPs, the apparatus comprising:
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a detection point identifier for identifying detection points;
a selector which selects a compensation factor as a function of the detection point and the generating detector; and
a modifier which modifies the EDP as a function of the compensation factor. - View Dependent Claims (7, 8, 9, 10, 11)
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12. A programmed data processor for use with a PET scanner system including processing circuitry, and a plurality of detector units, each detector unit including a detection surface area, when a photon impacts a detection surface area at a detection point and an event time, the scanner generating an event detection pulse (EDP), scanner hardware which processes impacting photons causing varying delays between event times and corresponding EDPs, the detector delay corresponding to each detector unit varying as a function of detection point, the processor for modifying the EDPs so that the timing of each EDP is essentially temporally accurate relative to all other EDPs, the processor performing the steps of:
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for each EDP;
identifying detection point;
selecting a compensation factor as a function of the detection point and the generating detector; and
modifying the EDP as a function of the compensation factor. - View Dependent Claims (13, 14, 15, 16)
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17. An apparatus to be used with a PET scanner that includes a plurality of detector modules, each detector module including at least two detector units that together form a surface area, when a photon impacts the surface area at an impact point and an event time, one of the detector units generating an event detection pulse (EDP), scanner hardware that processes impacting photons causing varying delay between event times and corresponding EDPs, the apparatus for modifying the EDPs so that the timing of each EDP is essentially accurate relative to all other EDPs, the apparatus comprising:
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a timing pick-off circuit linked to the detector module for identifying the time of an EDP;
a detector unit identifier that identifies the detector unit that generates an EDP;
a multiplexer linked to the identifier and that includes a separate input for each of the detector units and a single output, the multiplexer passing the EDP to the output;
a delay unit linked to the multiplexer output and the identifier, the delay unit selecting a compensation delay as a function of the detector unit and delaying the EDP by the compensation delay to generate a delayed EDP. - View Dependent Claims (18, 19, 20, 21, 22)
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Specification