Method and apparatus for real-time tumor tracking

• US 20070265528A1
• Filed: 04/10/2007
• Published: 11/15/2007
• Est. Priority Date: 04/10/2006
• Status: Active Grant

• Current Assignee: Jerry Wong, Sabee Molloi, Tong Xu
• Original Assignee: Jerry Wong, Sabee Molloi, Tong Xu
• Inventors: Molloi, Sabee, Xu, Tong, Wong, Jerry
• Granted Patent: US 8,447,387 B2
• Time in Patent Office: Days
• US Class Current: 600/426
• CPC Class Codes: A61B 6/4258 for detecting non x-ray radiation, e.g. gamma radiation A61B6/037 takes precedence
• CPC Class Codes: G01T 1/2985 In depth localisation, e.g. using positron emitters; Tomographic imaging (longitudinal and transverse section imaging; apparatus for radiation diagnosis sequentially in different planes, steroscopic radiation diagnosis); using external radiation sources A61B6/02

Abstract

Method and apparatus for real-time tracking of a target in a human body. In one embodiment of the invention, positron emission marker may be implanted into a target, the positron emission marker having a low activity positron isotope. In one embodiment, annihilation gamma rays associated with the low activity positron isotope may be detected using a plurality of position-sensitive detectors. In another embodiment, the target may be tracked in real-time based on a position of the positron emission marker.

Claims

1. A method for real-time tracking of a target in a human body, the method comprising the acts of:

implanting a positron emission marker in the target having a low activity positron isotope;

detecting annihilation gamma rays associated with the low activity positron isotope using a plurality of position-sensitive detectors; and

tracking the target in real-time based on a position of the positron emission marker.

2. The method of claim 1, further comprising:

forming a coincident line for each pair of the detected annihilation gamma rays; and

sorting the coincident lines into clusters based on an iterative Expectation-Maximization clustering algorithm.

3. The method of claim 2, wherein said tracking further comprises identifying a location of the positron emission marker using each of said coincident line clusters.

4. The method of claim 1, wherein said tracking further comprises tracking the target with sub-millimeter accuracy.

5. The method of claim 1, further comprising determining marker migration using at least one fiducial marker.

6. The method of claim 1, wherein said target is selected from the list consisting of:

a tumor, an internal body structure and a medical instrument.

7. The method of claim 1, wherein said low activity positron isotope is selected from the list consisting of:

I-124, As-74, Rb-84, Na-22, Al-26, Ge-68, V-48 and Co-58.

8. The method of claim 1, wherein said implanting comprises implanting a plurality of different positron emission markers in said target.

9. The method of claim 8, wherein at least one of the plurality of positron emission markers includes a plurality of low activity positron isotopes.

10. The method of claim 9, further comprising identifying the plurality of different positron emission markers with the plurality of low activity positron isotopes using said annihilation gamma rays.

11. The method of claim 10, further comprising determining an orientation of said target using a relative position of said identified plurality of different positron emission markers.

12. An apparatus for tracking a target in a human body, comprising:

a plurality of detectors arranged near a radiation isocenter;

a gantry configured to support said plurality of detectors, wherein said plurality of detectors is configured to detect annihilation gamma rays associated with a positron emission marker; and

a module configured to track a position of said target in real-time based on a position of the positron emission marker.

13. The apparatus of claim 12, wherein said module is further configured to:

form a coincident line for each pair of detected annihilation gamma rays; and

sort coincident lines into clusters based on an iterative Expectation-Maximization clustering algorithm.

14. The apparatus of claim 13, wherein said module is further configured to identify a location of the positron emission marker using each of said coincident line clusters.

15. The apparatus of claim 12, wherein said module is further configured to track said target with sub-millimeter accuracy.

16. The apparatus of claim 12, wherein said module is further configured to determine marker migration using at least one fiducial marker.

17. The apparatus of claim 12, wherein said target is selected from the list consisting of:

a tumor, an internal body structure and a medical instrument.

18. The apparatus of claim 12, wherein said low activity positron isotope is selected from the list consisting of:

I-124, As-74, Rb-84, Na-22, Al-26, Ge-68, V-48 and Co-58 isotopes.

19. The apparatus of claim 12, wherein said module is further configured to track a plurality of different positron emission markers in said target.

20. The apparatus of claim 19, wherein at least one of the plurality of different positron emission markers include a plurality of low activity positron isotopes.

21. The apparatus of claim 20, wherein said module is further configured to identify the plurality of different positron emission markers with the plurality of low activity positron isotopes by their accompanying gamma rays.

22. The apparatus of claim 21, wherein said module is further configured to determine an orientation of said target using a relative position of said identified markers.

23. A system for radiation therapy based on real-time three-dimensional position and orientation of a target, comprising:

at least one positron emission marker in said target, said at least one positron emission marker labeled with a low activity positron isotope;

a plurality of detectors arranged near a radiation isocenter configured to detect annihilation gamma rays associated with at least one positron emission marker; and

a module configured to track a position of said target in real-time based on said position of said at least one positron emission marker.

24. The system of claim 23, further comprising a synchronizing and gating system that temporally stop acquisition of detectors during an x-ray pulse.

25. The system of claim 23, wherein said module is further configured to:

form a coincident line for each pair of the detected annihilation gamma rays; and

sort the coincident lines into clusters based on an iterative Expectation-Maximization clustering algorithm.

26. The system of claim 25, wherein said module is further configured to identify a location of the positron emission marker using each of said coincident line clusters.

27. The system of claim 23, wherein said module is further configured to track the target with sub-millimeter accuracy.

28. The system of claim 23, wherein said module is further configured to determine marker migration using at least one fiducial marker.

29. The system of claim 23, wherein said target is selected from the list consisting of:

a tumor, an internal body structure and a medical instrument.

30. The system of claim 23, wherein said low activity positron isotope is selected from the list consisting of:

I-124, As-74, Rb-84, Na-22, Al-26, Ge-68, V-48 and Co-58.

31. The system of claim 23, wherein said module is further configured to track a plurality of different positron emission markers in said target.

32. The system of claim 31, wherein at least one of the plurality of different positron emission markers include a plurality of low activity positron isotopes.

33. The system of claim 32, wherein said module is further configured to identify the plurality of different positron emission markers labeled with the plurality of isotopes by their accompanying gamma rays.

34. The system of claim 33, wherein said module is further configured to determine an orientation of said target using a relative position of said identified plurality of different positron emission markers.