COMPONENT METHOD AND SYSTEM FOR PET DETECTOR EFFICIENCY NORMALIZATION

Abstract

A method and apparatus for calibrating a PET scanner is provided. First phantom sinogram data is acquired from a scan of a solid cylinder phantom within a PET scanner imaging FOV; second phantom sinogram data is acquired from a scan of a second solid plane or scanning line phantom within the PET scanner imaging FOV; and a PET scanner detector component scanner efficiency normalization is determined from at least one of the first and second sinogram data. In one aspect a crystal determining efficiency factor is determined as a function of phantom sinogram data without a solid angle correction, and a detector geometry factor is determined as a function of the crystal efficiency factor and phantom sinogram data. In one aspect a smoothed crystal efficiency normalization factor is determined from a noisy crystal efficiency factor through an iterative smoothing technique.

Description

FIGURES

FIG. 1 depicts a PET system.

FIG. 2 is a set of graphical illustrations of a PET scanner FOV taken along a transverse direction.

FIG. 3 is another set of graphical illustrations of a PET scanner FOV taken along a transverse direction.

FIG. 4 is another set of graphical illustrations of a PET scanner FOV taken along a transverse direction.

FIG. 5 provides a transverse view of an LOR sinogram from a plane phantom source.

FIG. 6 is another set of graphical illustrations of a PET scanner FOV taken along a transverse direction.

Claims

1. A method for calibrating a PET scanner, comprising the steps of: acquiring first phantom sinogram data from a scan of a solid cylinder phantom within a PET scanner imaging FOV;acquiring second phantom sinogram data from a scan of a second phantom within the PET scanner imaging FOV, the second phantom selected from the group comprising a solid plane phantom and a scanning line phantom; anddetermining a PET scanner detector component scanner efficiency normalization from at least one of the first and second sinogram data.

2. The method of claim 1, wherein the step of determining the PET scanner detector component scanner efficiency normalization comprises the steps of: modeling a noisy crystal efficiency factor Ei as a function of at least one of the first and second sinogram data by the following Equation C:

3. The method of claim 1, wherein one of the steps of acquiring first phantom sinogram data and acquiring second phantom sinogram data comprises acquiring first and second data files, further comprising the steps of: deriving a crystal efficiency factor or a detector geometry factor for an acquiring one of the first and second reconstruction imaging FOV's from the first data file; andmapping the derived crystal efficiency factor or the derived detector geometry factor to the second file for an other of the first and second reconstruction imaging FOV's.

4. The method of claim 1 wherein the PET scanner imaging FOV comprises first and second reconstruction imaging FOV's, the first reconstruction imaging FOV having a transverse cross-sectional area smaller than a second reconstruction imaging FOV transverse cross-sectional area; wherein the step of acquiring the first phantom sinogram data comprises scanning the solid cylinder phantom within the first reconstruction imaging FOV; andwherein the step of acquiring the second phantom sinogram data comprises scanning the second phantom source within the second reconstruction imaging FOV.

5. The method of claim 4, wherein the step of scanning the solid cylinder phantom within the first reconstruction imaging FOV comprises the step of the solid cylinder presenting a transverse cross-sectional scan area equal to or greater than the first reconstruction imaging FOV cross-sectional area; and wherein the step of scanning the second phantom source within the second reconstruction imaging FOV comprises the step of the second phantom presenting a linear transverse cross-sectional scan area equal to or greater than a transverse width of the second reconstruction imaging FOV cross-sectional area.

6. The method of claim 1 wherein the step of determining the PET scanner detector component scanner efficiency normalization comprises the steps of: determining a crystal efficiency factor as a function of phantom sinogram data, wherein the crystal efficiency factor is derived without a solid angle correction;determining a detector geometry factor as a function of the crystal efficiency factor and the phantom sinogram data; anddetermining the PET scanner detector component scanner efficiency normalization from only the crystal efficiency factor and the detector geometry factor,

7. The method of claim 6, wherein one of the steps of acquiring first phantom sinogram data and acquiring second phantom sinogram data comprises acquiring first and second data files, further comprising the steps of: deriving one of the crystal efficiency factor and the detector geometry factor for an acquiring one of the first and second reconstruction imaging FOV's from the first data file; andmapping the derived one of the crystal efficiency factor and the detector geometry factor to the second file for an other of the first and second reconstruction imaging FOV's.

8. The method of claim 6 wherein the step of determining the crystal efficiency factor comprises the steps of: determining a noisy crystal efficiency factor; anddetermining a smoothed crystal efficiency normalization factor from the noisy crystal efficiency factor through an iterative smoothing technique.

9. The method of claim 8, wherein the iterative smoothing technique comprises the steps of: modeling an individual detector crystal efficiency factor Ei by the following Equation C:

10. A method for calibrating a PET scanner, comprising the steps of: acquiring first phantom sinogram data from a scan of a first phantom within a first PET scanner reconstruction imaging FOV;acquiring second phantom sinogram data from a scan of a second phantom within a second PET scanner reconstruction imaging FOV; the second reconstruction imaging FOV having a transverse cross-sectional area larger than a first reconstruction imaging FOV transverse cross-sectional area;determining a crystal efficiency factor as a function of at least one of the first and second sinogram data, wherein the crystal efficiency factor is derived without a solid angle correction;determining a detector geometry factor as a function of the crystal efficiency factor and at least one of the first and second sinogram data; anddetermining a PET scanner detector component scanner efficiency normalization from only the crystal efficiency factor and the detector geometry factor.

11. A method for calibrating a PET scanner, comprising the steps of: acquiring phantom sinogram data comprising first and second data files from a scan of a phantom within a PET scanner imaging FOV, wherein the first data file has a first phantom geometry, and the second data file has a second phantom geometry; anddetermining a PET scanner detector component scanner efficiency normalization from the sinogram data.

12. The method of claim 11 wherein the wherein the first data file has a first reconstruction imaging FOV transverse cross-sectional area, and the second data file has a second reconstruction imaging FOV transverse cross-sectional area larger than the first reconstruction imaging FOV transverse cross-sectional area.

13. The method of claim 11 wherein the step of acquiring phantom sinogram data comprising first and second data files from a scan of a phantom within a PET scanner imaging FOV comprises the steps of: acquiring the first data file by scanning a solid cylinder phantom within the first reconstruction imaging FOV; andacquiring the second data file by scanning a second phantom within the second reconstruction imaging FOV, the second phantom selected from the group comprising a solid plane phantom and a scanning line phantom.

14. A method for determining a PET scanner crystal efficiency factor, comprising the steps of: acquiring phantom sinogram data from a scan of a phantom within a PET scanner imaging FOV;modeling a noisy crystal efficiency factor from the sinogram data;determining a smoothed crystal efficiency factor estimate from the noisy crystal efficiency factor;repeating the modeling and determining steps until the smoothed crystal efficiency factor estimate converges within a specified difference from a prior smoothed crystal efficiency factor estimate.

15. An apparatus for calibrating a PET scanner, comprising: a processor configured to acquiring first phantom sinogram data from a scan of a solid cylinder phantom within a PET scanner imaging FOV;the processor further configured to acquire second phantom sinogram data from a scan of a second phantom within the PET scanner imaging FOV, the second phantom selected from the group comprising a solid plane phantom and a scanning line phantom; andthe processor further configured to determine a PET scanner detector component scanner efficiency normalization from at least one of the first and second sinogram data.

16. The apparatus of claim 15, wherein the processor is configured to acquire the first phantom sinogram data or the second phantom sinogram data by acquiring first and second data files; the processor further configured to derive a crystal efficiency factor or a detector geometry factor for an acquiring one of the first and second reconstruction imaging FOV's from the first data file; andmap the derived crystal efficiency factor or the derived detector geometry factor to the second file for an other of the first and second reconstruction imaging FOV's.

17. The apparatus of claim 15 wherein the PET scanner imaging FOV comprises first and second reconstruction imaging FOV's, the first reconstruction imaging FOV having a transverse cross-sectional area smaller than a second reconstruction imaging FOV transverse cross-sectional area; wherein the processor is configured to acquire the first phantom sinogram data by scanning the solid cylinder phantom within the first reconstruction imaging FOV; andwherein the processor is configured to acquire the second phantom sinogram data by scanning the second phantom source within the second reconstruction imaging FOV.

18. The apparatus of claim 15 wherein the processor is configured to determine the PET scanner detector component scanner efficiency normalization by: determining a crystal efficiency factor as a function of phantom sinogram data, the crystal efficiency factor derived without a solid angle correction;determining a detector geometry factor as a function of the crystal efficiency factor and the phantom sinogram data; anddetermining the PET scanner detector component scanner efficiency normalization from only the crystal efficiency factor and the detector geometry factor.

19. The apparatus of claim 18, wherein the processor is configured to acquire the first phantom sinogram data or the second phantom sinogram data by acquiring first and second data files; the processor further configured to derive one of the crystal efficiency factor and the detector geometry factor for an acquiring one of the first and second reconstruction imaging FOV's from the first data file; andmap the derived one of the crystal efficiency factor and the detector geometry factor to the second file for an other of the first and second reconstruction imaging FOV's.

20. The apparatus of claim 18 wherein the processor is configured to determine the crystal efficiency by: determining a noisy crystal efficiency factor; anddetermining a smoothed crystal efficiency normalization factor from the noisy crystal efficiency factor through an iterative smoothing technique.

21. The apparatus of claim 20, wherein the iterative smoothing technique comprises the steps of: modeling an individual detector crystal efficiency factor Ei by the following Equation C:

22. An article of manufacture comprising a computer usable medium having a computer readable program embodied in said medium, wherein the computer readable program, when executed on a computer, causes the computer to calibrate a PET scanner by: acquiring first phantom sinogram data from a scan of a solid cylinder phantom within a PET scanner imaging FOV;acquiring second phantom sinogram data from a scan of a second phantom within the PET scanner imaging FOV, the second phantom selected from the group comprising a solid plane phantom and a scanning line phantom; anddetermining a PET scanner detector component scanner efficiency normalization from at least one of the first and second sinogram data.

23. The article of manufacture of claim 22, wherein the computer readable program, when executed on the computer, causes the computer to: acquire the first phantom sinogram data or the second phantom sinogram data by acquiring first and second data files;derive a crystal efficiency factor or a detector geometry factor for an acquiring one of the first and second reconstruction imaging FOV's from the first data file; andmap the derived crystal efficiency factor or the derived detector geometry factor to the second file for an other of the first and second reconstruction imaging FOV's.

24. The article of manufacture of claim 22, wherein the PET scanner imaging FOV comprises first and second reconstruction imaging FOV's, the first reconstruction imaging FOV having a transverse cross-sectional area smaller than a second reconstruction imaging FOV transverse cross-sectional area, and wherein the computer readable program, when executed on the computer, causes the computer to: acquire the first phantom sinogram data by scanning the solid cylinder phantom within the first reconstruction imaging FOV; andacquire the second phantom sinogram data by scanning the second phantom source within the second reconstruction imaging FOV.

25. The article of manufacture of claim 22 wherein the computer readable program, when executed on the computer, causes the computer to determine the PET scanner detector component scanner efficiency normalization by: determining a crystal efficiency factor as a function of phantom sinogram data, the crystal efficiency factor derived without a solid angle correction;determining a detector geometry factor as a function of the crystal efficiency factor and the phantom sinogram data; anddetermining the PET scanner detector component scanner efficiency normalization from only the crystal efficiency factor and the detector geometry factor.

26. The article of manufacture of claim 25, wherein the computer readable program, when executed on the computer, causes the computer to: acquire the first phantom sinogram data or the second phantom sinogram data by acquiring first and second data files;derive one of the crystal efficiency factor and the detector geometry factor for an acquiring one of the first and second reconstruction imaging FOV's from the first data file; andmap the derived one of the crystal efficiency factor and the detector geometry factor to the second file for the other of the first and second reconstruction imaging FOV's.

27. The article of manufacture of claim 25 wherein the computer readable program, when executed on the computer, causes the computer to determine the crystal efficiency by: determining a noisy crystal efficiency factor; anddetermining a smoothed crystal efficiency normalization factor from the noisy crystal efficiency factor through an iterative smoothing technique.

28. The article of manufacture of claim 27, wherein the iterative smoothing technique comprises the steps of: modeling an individual detector crystal efficiency factor Ei by the following Equation C: