System and method for correcting timing errors in a medical imaging system

1. A method of correcting a timing signal that represents an arrival time of a photon at a Positron Emission Tomography (PET) detector, said method comprising:

receiving a timing signal that represents an arrival time of a photon at a PET detector;

receiving an energy signal indicative of an energy of the photon;

calculating a timing correction using the energy signal;

modifying the timing signal using the timing correction; and

generating an image of an object using the modified timing signal, wherein the energy signal includes a direct current (DC) offset, the timing correction being based on the DC offset.

2. The method of claim 1 , wherein calculating a timing correction further comprises:

measuring the DC offset in the energy signal;

generating a cancellation signal based on the determined DC offset; and

utilizing the cancellation signal to modify a gamma ray event detection threshold of a primary discriminator.

3. The method of claim 1 , wherein calculating a timing correction further comprises:

measuring a plurality of values of the energy signal;

determining time periods when no photons have interacted in the detector;

utilizing the values of the energy signal measured during these time periods to determine a plurality of DC offsets of the energy signal for the time periods; and

utilizing the determined DC offsets to calculate the timing correction.

4. The method of claim 3 , further comprising comparing the determined DC offsets to values stored in a look-up table to calculate the timing correction.

5. The method of claim 3 , further comprising:

continuously measuring the plurality of DC offsets; and

continuously determining an average of at least two of the DC offsets.

6. The method of claim 3 , wherein the difference between at least one of the determined DC offsets and a reference value is used to calculate the timing correction.

7. A method of correcting a timing signal that represents an arrival time of a photon at a Positron Emission Tomography (PET) detector, said method comprising:

receiving a timing signal that represents an arrival time of a photon at a PET detector;

receiving an energy signal indicative of an energy of the photon;

calculating a timing correction using the energy signal;

modifying the timing signal using the timing correction; and

generating an image of an object using the modified timing signal, wherein calculating a timing correction further comprises:

measuring the DC offset in the energy signal;

generating an analog cancellation signal based on the determined DC offset; and

applying the analog cancellation signal to the timing signal to modify the timing signal.

8. An imaging system comprising:

a plurality of detectors supported by a gantry;

a plurality of acquisition circuits coupled to the detectors, wherein the acquisition circuits provide event detection signals; and

a field programmable gate array (FPGA) utilized to record the event detection signals, said FPGA programmed to:

receive a timing signal that represents an arrival time of a photon at a PET detector;

receive an energy signal indicative of an energy of the photon;

calculate a timing correction using the energy signal;

modify the timing signal using the timing correction; and

generate an image of an object using the modified timing signal, wherein the energy signal includes a direct current (DC) offset, the timing correction being based on the DC offset.

9. The system of claim 8 , wherein to calculate a timing correction, said FPGA is further programmed to:

measure the DC offset in the energy signal;

generate an analog cancellation signal based on the determined DC offset; and

modify a gamma ray event detection threshold of a primary discriminator using the analog cancellation signal.

10. The system of claim 8 , wherein to calculate a timing correction, said FPGA is further programmed to:

measure a plurality of the DC offsets in the energy signal;

determine a difference between at least two of the DC offsets; and

calculate the timing correction using the determined difference in offsets.

11. The system of claim 10 , wherein the FPGA is further programmed to compare the determined difference in the DC offsets to values stored in a look-up table to calculate the timing correction.

12. The system of claim 10 , wherein the FPGA is further programmed to:

continuously measure the plurality of DC offsets; and

continuously determine the difference between at least two of the DC offsets.

13. The system of claim 10 , wherein the difference between the determined DC offset and a reference value is used to calculate the timing correction.

14. An imaging system comprising:

a plurality of detectors supported by a gantry;

a plurality of acquisition circuits coupled to the detectors, wherein the acquisition circuits provide event detection signals; and

a field programmable gate array (FPGA) utilized to record the event detection signals, said FPGA programmed to:

receive a timing signal that represents an arrival time of a photon at a PET detector;

receive an energy signal indicative of an energy of the photon;

calculate a timing correction using the energy signal;

modify the timing signal using the timing correction; and

generate an image of an object using the modified timing signal, wherein the energy signal includes a direct current (DC) offset, the timing correction being based on the DC offset, wherein to calculate a timing correction, said FPGA is further programmed to:

measure a direct current (DC) offset in the energy signal;

generate an analog cancellation signal based on the determined DC offset; and

apply the analog cancellation signal to the timing signal to modify the timing signal.

15. A non-transitory computer readable medium programmed to instruct a computer of a Positron Emission Tomography (PET) system to:

receive a timing signal that represents an arrival time of a photon at a PET detector;

receive an energy signal indicative of an energy of the photon;

calculate a timing correction using the energy signal;

modify the timing signal using the timing correction; and

generate an image of an object using the modified timing signal, wherein the energy signal includes a direct current (DC) offset, the timing correction being based on the DC offset.

16. A non-transitory computer readable medium programmed to instruct a computer of a Positron Emission Tomography (PET) system to:

receive a timing signal that represents an arrival time of a photon at a PET Detector;

receive an energy signal indicative of an energy of the photon;

calculate a timing correction using the energy signal;

modify the timing signal using the timing correction; and

generate an image of an object using the modified timing signal, further programmed to instruct the computer to:

measure a plurality of DC offsets in the energy signal;

determine a difference between at least two of the DC offsets; and

calculate the timing correction using the determined difference.

17. The non-transitory computer readable medium of claim 16 , further programmed to instruct the computer to compare the determined difference to values stored in a look-up table to calculate the timing correction.