Method and system for predictive physiological gating of radiation therapy

• US 6,621,889 B1
• Filed: 10/23/1998
• Issued: 09/16/2003
• Est. Priority Date: 10/23/1998
• Status: Expired due to Term

• Current Assignee: Varian Medical Systems Incorporated (Siemens AG)
• Original Assignee: Varian Medical Systems Incorporated (Siemens AG)
• Inventors: Mostafavi, Hassan
• Primary Examiner(s): Church, Craig E.
• Application Number:
  US09/178,383
• Time in Patent Office: 1,789 Days
• Field of Search: 378/95, 378/65
• US Class Current: 378/65
• CPC Class Codes: A61B 6/541 involving acquisition triggered by a physiological signal
• CPC Class Codes: A61N 5/1037 taking into account the movement of the target, e.g. 4D-image based planning
• CPC Class Codes: A61N 5/1048 Monitoring, verifying, controlling systems and methods
• CPC Class Codes: A61N 5/1064 for adjusting radiation treatment in response to monitoring

Abstract

A method and system for physiological gating for radiation therapy is disclosed. A method and system for detecting and predictably estimating regular cycles of physiological activity or movements is disclosed. Another disclosed aspect of the invention is directed to predictive actuation of gating system components. Yet another disclosed aspect of the invention is directed to physiological gating of radiation treatment based upon the phase of the physiological activity.

Claims

1. A method of gating the application of therapeutic radiation comprising:

measuring a first set of signal data representative of a physiological movement of a patient during a first time period;

pattern matching the first set of signal data with a second set of signal data related to measured physiological movement of a patient during a second time period to identify degree of deviation from periodicity of the physiological movement; and

gating therapeutic radiation to the patient if the degree of deviation from periodicity exceeds a threshold.

2. The method of claim 1 in which the first set of signal data and the second set of signal data are pattern matched using an autocorrelation function.

3. The method of claim 1 in which the first set of signal data and the second set of signal data are pattern matched using an absolute difference function.

4. The method of claim 1 further comprising:

determining a degree of match between the first set of signal data and the second set of signal data.

5. The method of claim 4 in which the degree of match is determined by a secondary peak value of an autocorrelation function.

6. The method of claim 4 in which the degree of match is determined by a secondary minimum value of an absolute difference function.

7. The method of claim 4 further comprising:

comparing the degree of match to a threshold range.

8. The method of claim 7 in which the degree of match outside the threshold range indicates deviation from a normal physiological movement.

9. The method of claim 7 in which the degree of match within the threshold range indicates a repetitive physiological movement.

10. The method of claim 9 in which a point of best match indicates a period of the physiological movement.

11. The method of claim 1 further comprising:

predicting a period of the physiological movement during a third time period.

12. The method of claim 11 further comprising:

predictively actuating a gating system component based upon the predicted period.

13. The method of claim 1 further comprising:

determining a period of the physiological movement.

14. The method of claim 13 further comprising:

defining a treatment interval to apply the therapeutic radiation to a patient.

15. The method of claim 14 in which the treatment interval is defined by phase of the physiological movement.

16. The method of claim 1 in which the second set of signal data is a data model of the physiological movement of the patient.

17. A method of gating the application of radiation, comprising:

measuring signal data representative of at least a portion of a physiological movement to form a set of ordered measurement samples;

pattern matching the set of ordered measurement samples against prior measurement samples of the physiological movement to determine deviation from periodicity of the set of ordered measurement samples; and

gating therapeutic radiation to the patient if the deviation from periodicity is outside a threshold range.

18. The method of claim 17 in which the second set of ordered measurement samples overlaps with the prior measurement samples.

19. The method of claim 17 in which the physiological movement comprises breathing movement.

20. The method of claim 17 in which pattern matching is performed using an autocorrelation function.

21. The method of claim 17 in which pattern matching is performed using an absolute difference function.

22. The method of claim 17 further comprising;

defining a treatment interval to apply radiation to a patient.

23. The method of claim 22 in which the treatment interval is defined based upon phase of the physiological movement.

24. The method of claim 17 further comprising:

determining a predicted value for an additional measurement sample for the physiological movement.

25. The method of claim 24 in which radiation gating occurs if the predicted value deviates from the additional measurement sample beyond a designated threshold level.

26. The method of claim 17 in which the step of pattern matching comprises shifting the set of ordered measurement samples against the prior measurement samples at a plurality of offset sample positions to determine position of best match.

27. The method of claim 26 in which an absolute difference function is used to determine the position of best match.

28. The method of claim 26 in which a search range for position of best match is established based upon a predicted position, in which the predicted position is based upon a period established from the prior measurement samples.