Real-time margin adaptation

Patent metadata

Field	Value
Publication number	US-10625100-B2
Application number	US-201515306882-A
Country	US
Kind code	B2
Filing date	Apr 27, 2015
Priority date	Apr 28, 2014
Publication date	Apr 21, 2020
Grant date	Apr 21, 2020

Abstract

Systems and methods directed to real-time treatment margin adaptation based on in-treatment imaging are provided. The system and method may utilize the potential of motion mitigation techniques such as couch tracking, DMLC, beam tracking, and the like to freeze tumor motion within the treatment aperture. A standard internal target volume (ITV) based margin plan and a minimum margin plan is created for the patient. The minimum margin plan assumes frozen intrafractional tumor motion. Depending on tumor location confidence in the motion mitigation technique, MLC leaf positions can be interpolated between the two plans to adjust margins during treatment delivery. If motion mitigation fails, the plan can be disabled resulting in the delivery of the current clinical standard of care. Dynamic aperture tracking may be employed with an electronic portal imaging device as the in-treatment imaging modality.

First claim

The invention claimed is:

1. A method for real-time treatment margin modification for use in radiotherapy treatment of a tumor of a subject, the method comprising:
acquiring image data from the tumor of the subject using an imaging system;
processing using a processor in communication with the imaging system, the image data;
generating a first treatment plan for radiation therapy having a first set of treatment margins based on an internal target volume (ITV) of the processed image data, the ITV encompassing an observed tumor motion range;
generating a second treatment plan for radiation therapy having a second set of treatment margins based on a contour of a gross tumor volume (GTV) of the same processed image data used to generate the first treatment plan; and
during delivery of the radiotherapy treatment to the subject in real-time:
calculating a tracking confidence parameter dependent on a confidence level in at least one of target localization or motion mitigation;
selecting the first treatment plan when the tracking confidence parameter is below a first predetermined threshold;
selecting the second treatment plan when the tracking confidence parameter is above a second predetermined threshold;
generating and selecting a third treatment plan for radiation therapy having a third set of treatment margins between the first set of treatment margins and the second set of treatment margins when the tracking confidence parameter is between the first predetermined threshold and the second predetermined threshold; and
communicating a selected one of the first treatment plan, the second treatment plan, or the third treatment plan.

2. The method of claim 1 , wherein the second set of treatment margins is smaller than the first set of treatment margins.

3. The method of claim 1 , further comprising utilizing a 4D planning approach for intra-fractional motion based on at least one of 4DCT or 4D MR images to generate the first treatment plan.

4. The method of claim 1 , wherein generating the first treatment plan includes generating the first set of treatment margins representative of a current standard of care.

5. The method of claim 1 , wherein generating the second treatment plan includes generating the second set of treatment margins based on an assumption of negligible intrafractional target motion due to successful motion mitigation.

6. The method of claim 1 , further comprising disabling motion mitigation when the tracking confidence parameter is below the first predetermined threshold.

7. The method of claim 1 , further comprising enabling motion mitigation when the tracking confidence parameter is above the first predetermined threshold.

8. The method of claim 1 , wherein the first, second and third set of treatment margins each correspond with at least one leaf position of a multi-leaf collimator (MLC) for delivering radiation to the tumor.

9. The method of claim 8 , further comprising generating the third set of treatment margins by applying a linear interpolation of the at least one leaf position of the first set of treatment margins and the second set of treatment margins.

10. The method of claim 9 , further comprising weighting the at least one leaf position of the first treatment margin and the second treatment margin by the tracking confidence parameter when the tracking confidence parameter is between the first predetermined threshold and the second predetermined threshold.

11. The method of claim 1 , further comprising operating a radiotherapy system according to the selected one of the first treatment plan, the second treatment plan, or the third treatment plan.

12. A system for real-time treatment margin modification for use in radiotherapy treatment of a tumor of a subject comprising:
an imaging system configured to acquire image data from the tumor of the subject;
a processor in communication with the imaging system, the processor configured to:
process the image data from the tumor of the subject acquired by the imaging system;
generate a first treatment plan for radiation therapy having a first set of treatment margins based on an internal target volume (ITV) of the processed image data, the ITV encompassing an observed tumor motion range; and
generate a second treatment plan for radiation therapy having a second set of treatment margins based on a contour of a gross tumor volume (GTV) of the same processed image data used to generate the first treatment plan; and
during delivery of the radiotherapy treatment to the subject in real-time:
calculate a tracking confidence parameter dependent on a confidence level in at least one of target localization or motion mitigation;
select the first treatment plan when the tracking confidence parameter is below a first predetermined threshold;
select the second treatment plan when the tracking confidence parameter is above a second predetermined threshold;
generate and select a third treatment plan for radiation therapy having a third set of treatment margins between the first set of treatment margins and the second set of treatment margins when the tracking confidence parameter is between the first predetermined threshold and the second predetermined threshold; and
communicate the selected one of the first treatment plan, the second treatment plan, or the third treatment plan to a radiotherapy system to perform the radiation therapy treatment.

13. The system of claim 12 , wherein the second set of treatment margins is smaller than the first set of treatment margins.

14. The system of claim 12 , wherein a 4D planning approach is utilized for intra-fractional motion based on at least one of 4DCT or 4D MR images to generate the first treatment plan.

15. The system of claim 12 , wherein the first treatment plan includes the first set of treatment margins representative of a current of standard care.

16. The system of claim 12 , wherein the second treatment plan includes the second set of treatment margins generated based on an assumption of negligible intrafractional target motion due to successful motion mitigation.

17. The system of claim 12 , wherein when the tracking confidence parameter is below the first predetermined threshold, motion mitigation is disabled.

18. The system of claim 12 , wherein when the tracking confidence parameter is above the first predetermined threshold, motion mitigation is enabled.

19. The system of claim 12 , wherein the first, second and third set of treatment margins each correspond with at least one leaf position of a multi-leaf collimator (MLC) for delivering radiation to the tumor.

20. The system of claim 19 , wherein the third set of treatment margins is generated by applying a linear interpolation of the at least one leaf position of the first set of treatment margins and the second set of treatment margins.

21. The system of claim 20 , wherein when the tracking confidence parameter is between the first predetermined threshold and the second predetermined threshold, the at least one leaf position of the first treatment margin and the second treatment margin is weighted by the tracking confidence parameter.

Assignees

• Brigham & Womens Hospital Inc

Inventors

• Berbeco Ross
• Rottmann Joerg

Classifications

• A61N5/1075

  for testing, calibrating, or quality assurance of the radiation treatment apparatus · CPC title

• A61N5/1037

  taking into account the movement of the target, e.g. 4D-image based planning · CPC title

• A61N2005/1055

  using magnetic resonance imaging [MRI] · CPC title

• A61N5/1067

  in real time, i.e. during treatment · CPC title

• A61N5/1064 Primary

  for adjusting radiation treatment in response to monitoring · CPC title