CMOS SPAD array with mixed timing pick-off for time-of-flight positron emission tomography
AssigneeSiemens Medical Solutions USA, Inc.
InventorsMatthias J. Schmand, Nan Zhang
Life of this patent
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Abstract
Timing pick-off is provided in time-of-flight positron emission using digital output photo sensors (e.g., SPAD or dSiPM). The timing-to-digital converter (TDC) is replaced for timing detection with a mixed analog and digital timing pick-off (MTP) where a processor determines the timing from an output of the MTP. The digital SPAD or dSiPM output is summed into an analog waveform, allowing for triggering based on signal statistics or other than at a particular number of discrete detections. The trigger is used by the processor to extrapolate the time of occurrence without an integrated TDC.
Claims14
A system for timing pick-off in time-of-flight positron emission tomography, the system comprising:
- an array of single photon avalanche diodes formed as complementary metal-oxide semiconductors;
- a summer connected with the single photon avalanche diodes of the array, the summer for analog summing pulses from the single photon avalanche diodes into a waveform of positron emission signal over time;
- a trigger circuit connected with the summer, the trigger circuit configured to generate a trigger signal based on a scintillation photon statistic of the waveform;
- and
- a timing circuit connected with the trigger circuit, the timing circuit configured to determine a start time of the trigger signal;
- wherein the photon statistic is a trigger threshold determined by a pulse lowest noise-to-slope ratio (NSR);
- and
- wherein the summer, trigger circuit, and timing circuit are free of a time-to-digital converter.
Dependencies are inferred from the claim text.