Radiation therapy system with multiple X-ray imagers for near real-time localization

Patent metadata

Field	Value
Publication number	US-11027153-B2
Application number	US-201916452505-A
Country	US
Kind code	B2
Filing date	Jun 25, 2019
Priority date	Jul 28, 2018
Publication date	Jun 8, 2021
Grant date	Jun 8, 2021

Abstract

A radiation therapy system is configured to enable imaging and treatment of a target volume during a single patient breath hold. The radiation system includes a rotating gantry on which are mounted a treatment-delivering X-ray source and multiple imaging X-ray sources and corresponding X-ray imaging devices. The multiple imaging X-ray sources and X-ray imaging devices enable the acquisition of volumetric image data for the target volume over a relatively short rotational arc, for example 30 degrees or less. Therefore, intra-fraction motion can be detected in near-real time, for example within about one second or less. The radiation therapy system can perform image guided radiation therapy (IGRT) that monitors intra-fraction motion using X-ray imaging. Detected anatomical variations can then either be compensated for, via patient repositioning and/or treatment modification, or the current treatment can be aborted.

First claim

We claim:

1. A radiation treatment system comprising:
a gantry that is rotatably coupled to a drive stand and is configured to rotate about a bore of the radiation treatment system;
a treatment-delivering X-ray source mounted on the gantry and configured to direct treatment X-rays to a target volume disposed in the bore;
a first imaging X-ray source mounted on the gantry and configured to direct first X-rays through the target volume and toward a first X-ray imager mounted on the gantry;
a second imaging X-ray source mounted on the gantry and configured to direct second X-rays through the target volume and toward a second X-ray imager mounted on the gantry; and
a processor configured to:
cause the gantry to perform a rotation continuously in a first direction, wherein the rotation includes an imaging arc and a treatment arc that follows the imaging arc and starts at a first treatment delivery position;
while causing the gantry to rotate through the imaging arc from a first imaging position to the first treatment delivery position, receive first volumetric image data from the first X-ray imager and second volumetric image data from the second X-ray imager;
determine a first current location of the target volume based on the first volumetric image data and the second volumetric image data; and
in response to a determination that the first current location of the target volume is less than a threshold distance from a planned treatment location, while causing the gantry to rotate through the treatment arc:
initiate delivery of a treatment beam of the treatment-delivering X-ray source to the target volume; and
continue to cause the gantry to rotate in the first direction from the first treatment delivery position to a second treatment delivery position.

2. The radiation treatment system of claim 1 , wherein:
the first imaging X-ray source is further configured to direct at least a portion of the first X-rays from a first source point associated with the first imaging X-ray source and toward the first X-ray imager along a first imaging beam path;
the second imaging X-ray source is further configured to direct at least a portion of the second X-rays from a second source point associated with the second imaging X-ray source and toward the second X-ray imager along a second imaging beam path; and
the first beam path is perpendicular to the second beam path.

3. The radiation treatment system of claim 2 , wherein the first beam path and the second beam path each pass through an isocenter of the radiation treatment system.

4. The radiation treatment system of claim 1 , further comprising a third X-ray imager that is mounted on the gantry, is disposed opposite the treatment-delivering X-ray source, and is configured to generate image data in response to delivery of the treatment beam to the target volume with the treatment-delivering X-ray source, wherein:
the first imaging X-ray source is mounted proximate a first side of the third X-ray imager;
the second imaging X-ray source is mounted proximate a second side of the third X-ray imager; and
the first side is opposite the second side.

5. The radiation treatment system of claim 1 , wherein the first imaging X-ray source and the first X-ray imager are configured to can be positioned on the gantry in a half-fan configuration.

6. The radiation treatment system of claim 1 , wherein the second imaging X-ray source and the second X-ray imager are configured to can be positioned on the gantry in a full-fan configuration.

7. The radiation treatment system of claim 6 , wherein the second imaging X-ray source and the second X-ray imager are configured to be adjustable from the full-fan configuration to a half-fan configuration.

8. The radiation treatment system of claim 1 , wherein an imager separation angle between the first imaging X-ray source and the second imaging X-ray source is less than or equal to 90 degrees.

9. The radiation treatment system of claim 1 , wherein:
the first imaging X-ray source is configured to direct the first X-rays through all portions of a smaller field-of-view region of the target volume and through a first portion of a larger field-of-view region of the target volume and none of the first X-rays through a second portion of the larger field-of-view region; and
the second imaging X-ray source is configured to direct the second X-rays through all portions of the smaller field-of-view region and through a third portion of the larger field-of-view region and none of the second X-rays through a fourth portion of the larger field-of-view region.

10. The radiation treatment system of claim 9 , wherein the first portion of the larger field-of-view region and the third portion of the larger field-of-view region overlap partially but not completely.

11. The radiation treatment system of claim 9 , wherein the second portion of the larger field-of-view region overlaps the third portion of the larger field-of-view region.

12. The radiation treatment system of claim 9 , wherein a first edge ray of the first X-rays coincides with an outer limit of the smaller field-of-view region and a second edge ray of the first X-rays coincides with an outer limit of the larger field-of-view region.

13. The radiation treatment system of claim 12 , wherein a third edge ray of the second X-rays coincides with the outer limit of the smaller field-of-view region and a fourth edge ray of the second X-rays coincides with the outer limit of the larger field-of-view region.

14. The radiation treatment system of claim 1 , wherein the processor is further configured to:
determine a second current location of a portion of the target volume based on the first volumetric image data and the second volumetric image data; and
in response to a determination that the second current location of the portion of the target volume is less than a threshold distance from a planned treatment location for the portion of the target volume, while causing the gantry to rotate through the treatment arc:
initiate delivery of the treatment beam of the treatment-delivering X-ray source to the portion of the target volume; and
continue to cause the gantry to rotate in the first direction from the first treatment delivery position to the second treatment delivery position.

15. A computer-implemented method of performing radiation therapy with a radiation system that includes a gantry that is rotatably coupled to a drive stand and is configured to rotate about a bore of the radiation treatment system through a rotation that includes an imaging arc and a treatment arc, the method comprising:
while causing the gantry to rotate in a first direction through the imaging arc from a first imaging position to a first treatment delivery position, receiving first volumetric image data from a first X-ray imager mounted on the gantry and second volumetric image data from a second X-ray imager mounted on the gantry;
determining a first current location of the target volume based on the first volumetric image data and the second volumetric image data; and
in response to a determination that the first current location of the target volume is less than a threshold distance from a planned treatment location, while causing the gantry to continue to rotate through the treatment arc from the first treatment delivery position:
initiating delivery of a treatment beam of a treatment-delivering X-ray source mounted on the gantry to the target volume; and
continuing to cause the gantry to rotate through the treatment arc in the first direction from the first treatment delivery position to a second treatment delivery po

Assignees

• Varian Med Sys Inc

Inventors

• Van Heteren John
• Zhu Liangjia
• Morf Daniel
• Scheib Stefan Georg
• Paysan Pascal

Classifications

• G06T12/30

  Image post-processing, e.g. metal artefact correction · CPC title

• A61N5/1067 Primary

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

• G06T7/0012

  Biomedical image inspection · CPC title

• A61N5/107

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

• A61N5/1049

  for verifying the position of the patient with respect to the radiation beam · CPC title