Non-linear correlation models for internal target movement

• US 8,027,715 B2
• Filed: 09/29/2005
• Issued: 09/27/2011
• Est. Priority Date: 10/02/2004
• Status: Active Grant

• Current Assignee: Accuray Incorporated
• Original Assignee: Accuray Incorporated
• Inventors: Sayeh, Sohail
• Primary Examiner(s): JAWORSKI, FRANCIS J
• Application Number:
  US11/239,789
• Publication Number:
  US 20060074299A1
• Time in Patent Office: 2,189 Days
• Field of Search: 600/411, 600/413, 600426-428, 600/429, 606/130, 378/62, 378/69, 378/205, 702/188
• US Class Current: 600/426
• CPC Class Codes: A61B 5/1127 using markers
• CPC Class Codes: A61B 5/113 occurring during breathing
• CPC Class Codes: A61B 6/4458 the source unit or the detector unit being attached to robotic arms
• CPC Class Codes: A61N 2005/1061 using an x-ray imaging system having a separate imaging source
• CPC Class Codes: A61N 5/1037 taking into account the movement of the target, e.g. 4D-image based planning
• CPC Class Codes: A61N 5/1049 for verifying the position of the patient with respect to the radiation beam
• CPC Class Codes: A61N 5/1064 for adjusting radiation treatment in response to monitoring
• CPC Class Codes: A61N 5/1067 in real time, i.e. during treatment
• CPC Class Codes: A61N 5/107 in real time, i.e. during treatment

Abstract

A method and apparatus to track non-linear internal target movement based on movement of an external marker.

Claims

1. A computer-implemented method, comprising:

receiving a plurality of data points representative of a corresponding plurality of positions over time of an external marker associated with respiration of a patient;

receiving a plurality of images of an internal target of the patient, the plurality of images corresponding in time to the plurality of data points;

developing, using a processing device, a non-linear correlation model of a non-linear path of movement of the target based on the plurality of data points and the plurality of images to correlate a plurality of positions of the internal target with the plurality of positions of the external marker, wherein developing the non-linear correlation model comprises;

generating an inspiration approximation associated with the non-linear path of movement of the target over an inspiration interval of the non-linear path;

generating an expiration approximation associated with the non-linear path of movement of the target over an expiration interval of the non-linear path; and

generating one or more matching approximations to link the inspiration approximation and the expiration approximation.

2. The method of claim 1, wherein the non-linear correlation model comprises a polynomial approximation of the non-linear path of movement of the target.

3. The method of claim 1, wherein the non-linear correlation model comprises a multi-linear model having a plurality of linear approximations connected at a non-zero angle.

4. The method of claim 1, wherein developing the non-linear correlation model comprises generating one or derivatives from the plurality of data points, the one or more derivatives comprising one or more directional indicators.

5. The method of claim 1, wherein the inspiration approximation and the expiration approximation are derived from at least partially overlapping data sets.

6. The method of claim 1, further comprising deriving a target position of the target based on the non-linear correlation model.

7. The method of claim 6, further comprising:

sending a position signal associated with the target position to a beam generator controller; and

controlling a beam generator to direct a beam at the target position.

8. The method of claim 1, wherein the non-linear correlation model comprises a two-dimensional model or a three-dimensional model.

9. An apparatus, comprising:

a data storage device to store a plurality of data points representative of a corresponding plurality of positions over time of an external marker, the data storage device to store a plurality of images of an internal target of the patient, the plurality of images corresponding in time to the plurality of data points; and

a processing device coupled to the data storage device, the processing device configured to;

develop a non-linear correlation model of a non-linear path of movement of the target based on the plurality of data points and the plurality of images to correlate a plurality of positions of the internal target with the plurality of positions of the external marker, wherein developing the non-linear correlation model comprises;

generate an inspiration approximation associated with the non-linear path of movement of the target over an inspiration interval of the non-linear path;

generate an expiration approximation associated with the non-linear path of movement of the target over an expiration interval of the non-linear path; and

generate one or more matching approximations to link the inspiration approximation and the expiration approximation.

10. The apparatus of claim 9, wherein the non-linear correlation model comprises a polynomial approximation of the non-linear path of movement of the target.

11. The apparatus of claim 9, wherein the non-linear correlation model comprises a multi-linear model having a plurality of linear approximations connected at a non-zero angle.

12. The apparatus of claim 9, wherein developing the non-linear correlation model comprises generating one or derivatives from the plurality of data points, the one or more derivatives comprising one or more directional indicators.

13. The apparatus of claim 9, wherein the inspiration approximation and the expiration approximation are derived from at least partially overlapping data sets.

14. The apparatus of claim 9, further comprising:

a beam generator controller operatively coupled with processing device, wherein the processing device is further configured to derive a target position of the target based on the non-linear correlation model and sending a position signal associated with the target position to the beam generator controller;

a beam generator operatively coupled with the beam generator controller to direct a beam at the target position.

15. A non-transitory machine readable storage medium having instructions thereon, which when executed by a processing device, cause the processing device to perform one or more operations comprising:

receiving a plurality of data points representative of a corresponding plurality of positions over time of an external marker associated with respiration of a patient;

receiving a plurality of images of an internal target of the patient, the plurality of images corresponding in time to the plurality of data points;

developing, using a processing device, a non-linear correlation model of a non-linear path of movement of the target based on the plurality of data points and the plurality of images to correlate a plurality of positions of the internal target with the plurality of positions of the external marker, wherein developing the non-linear correlation model comprises;

generating an inspiration approximation associated with the non-linear path of movement of the target over an inspiration interval of the non-linear path;

generating an expiration approximation associated with the non-linear path of movement of the target over an expiration interval of the non-linear path; and

generating one or more matching approximations to link the inspiration approximation and the expiration approximation.

16. The non-transitory machine readable storage medium of claim 15, wherein the non-linear correlation model comprises a polynomial approximation of the non-linear path of movement of the target.

17. The non-transitory machine readable storage medium of claim 15, wherein the non-linear correlation model comprises a multi-linear model having a plurality of linear approximations connected at a non-zero angle.

18. The non-transitory machine readable storage medium of claim 15, wherein developing the non-linear correlation model comprises generating one or derivatives from the plurality of data points, the one or more derivatives comprising one or more directional indicators.

19. The non-transitory machine readable storage medium of claim 15, wherein the inspiration approximation and the expiration approximation are derived from at least partially overlapping data sets.

20. The non-transitory machine readable storage medium of claim 15, wherein the one or more operations further comprise deriving a target position of the target based on the non-linear correlation model.

21. The non-transitory machine readable storage medium of claim 20, wherein the one or more operations further comprise:

sending a position signal associated with the target position to a beam generator controller; and

controlling a beam generator to direct a beam at the target position.