Path planning and collision avoidance for movement of instruments in a radiation therapy environment

• US 7,746,978 B2
• Filed: 10/08/2007
• Issued: 06/29/2010
• Est. Priority Date: 08/12/2003
• Status: Expired due to Fees

• Current Assignee: LOMA Linda University Medical Center (Mission Healthcare Services LLC)
• Original Assignee: LOMA Linda University Medical Center (Mission Healthcare Services LLC)
• Inventors: Moyers, Michael F., Lesyna, David A., Cheng, Chieh C.
• Primary Examiner(s): SONG, HOON K
• Application Number:
  US11/868,918
• Publication Number:
  US 20080187097A1
• Time in Patent Office: 995 Days
• Field of Search: 378/65, 378/68, 378/69, 378/205, 378/209, 378/117, 378/195, 378/196, 378/197
• US Class Current: 378/65
• CPC Class Codes: A61B 2090/3937 Visible markers
• CPC Class Codes: A61B 6/0442 made of non-metallic materials
• CPC Class Codes: A61B 6/4092 for producing synchrotron radiation
• CPC Class Codes: A61B 6/547 involving tracking of position of the device or parts of the device
• CPC Class Codes: A61N 2005/105 using a laser alignment system
• CPC Class Codes: A61N 2005/1059 using cameras imaging the patient
• CPC Class Codes: A61N 2005/1061 using an x-ray imaging system having a separate imaging source
• CPC Class Codes: A61N 2005/1062 using virtual X-ray images, e.g. digitally reconstructed radiographs [DRR]
• CPC Class Codes: A61N 2005/1087 Ions; Protons
• CPC Class Codes: A61N 2005/1097 Means for immobilizing the patient
• 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 5/1067 in real time, i.e. during treatment
• CPC Class Codes: A61N 5/1069 Target adjustment, e.g. moving the patient support
• CPC Class Codes: A61N 5/107 in real time, i.e. during treatment
• CPC Class Codes: A61N 5/1078 Fixed beam systems
• CPC Class Codes: B25J 9/1666 Avoiding collision or forbidden zones
• CPC Class Codes: G05B 15/02 electric
• CPC Class Codes: G05B 2219/45117 Medical, radio surgery manipulator

Abstract

A patient positioning system for use with a radiation therapy system that monitors the location of fixed and movable components and pre-plans movement of the movable components so as to inhibit movement if a collision would be indicated. The positioning system can also coordinate movement of multiple movable components for reduced overall latency in registering a patient. The positioning system includes external measurement devices which measure the location and orientation of objects, including components of the radiation therapy system, in space and can also monitor for intrusion into the active area of the therapy system by personnel or foreign objects to improve operational safety of the radiation therapy system.

Claims

1. A therapy delivery system, the system comprising:

a patient positioning structure configured to position a patient in multiple translational and multiple rotational axes and secure at least a portion of the patient substantially immobile at a desired treatment pose;

a therapy delivery assembly configured to deliver therapy along a delivery path, wherein at least one of the patient positioning structure and the therapy delivery assembly are movable to align the desired treatment pose of a therapy delivery target of the patient with the therapy delivery path and wherein a movement envelope of at least one of the patient positioning structure and the therapy delivery assembly intersects one or more other structures of the therapy delivery system;

a plurality of external measurement devices which obtain location measurements of at least the patient positioning structure and the therapy delivery assembly;

a motion sequence coordinator adapted to control the movement of at least one of the positioning structure and the therapy delivery assembly in response to a first movement command for at least one of the patient positioning structure and the therapy delivery assembly to position the patient in the desired pose; and

a controller which receives the location measurements of at least the patient positioning structure and the therapy delivery assembly from the plurality of external measurement devices and determines the first movement command and determines whether a collision is indicated for the first movement command and, if no collision is indicated, initiates a corresponding first movement by forwarding the first movement command to the motion sequence coordinator.

2. The system of claim 1, wherein the external measurement devices obtain optical images to obtain the location measurements.

3. The system of claim 1, further comprising a plurality of markers fixed to at least the patient positioning structure and the therapy delivery assembly and wherein the external measurement devices obtain location measurements of the markers.

4. The system of claim 1, further comprising at least one local position feedback device in operative communication with at least one of the patient positioning structure and the therapy delivery assembly wherein the at least one local position feedback device provides supplemental location data to the controller indicative of the location of the at least one of the patient positioning structure and the therapy delivery assembly.

5. The system of claim 1, further comprising a movable patient imaging system configured to obtain an image of the patient and wherein the controller determines the relative pose of the therapy delivery target with respect to the therapy path at least in part with image data from the patient imaging system.

6. The system of claim 1, wherein both the patient positioning structure and the therapy delivery assembly are movable and wherein the system determines the movement commands for concurrent movement of the patient positioning structure and the therapy delivery assembly to increase speed of acquisition of the desired pose.

7. The system of claim 1, wherein the external measurement devices also determines location of fixed objects adjacent the system and wherein the controller inhibits motion if any collision with such objects is indicated.

8. A path planning and collision avoidance control system for a therapy system, the control system comprising:

a plurality of external measurement devices arranged to obtain location measurements of components of the therapy system; and

a controller receiving location information from the plurality of external measurement devices and providing movement commands to movable components of the therapy system to automatically align the patient in multiple translational and multiple rotational axes in a desired translational and rotational pose wherein a movement envelope of at least some of the movable components intersect other components of the therapy system and wherein, upon receiving a first movement command and prior to initiating a corresponding first movement, the controller further determines a corresponding movement envelope of the movable components and wherein the controller evaluates the movement envelope to determine if a collision is indicated and initiates the first movement of the movable components if no collision is indicated.

9. The control system of claim 8, wherein aligning the patient in the desired pose comprises aligning a patient support with respect to a therapy aiming point to which the therapy system directs therapy.

10. The control system of claim 8, further comprising a movable patient imager system configured to obtain an image of the patient and a target isocenter, wherein the controller determines movement commands and trajectories for both the patient imager and other movable components subject to the movement commands and inhibits movement if a collision is indicated.

11. The control system of claim 8, further comprising a plurality of markers fixed to selected points of the therapy system and wherein the external measurement devices obtain location measurements of the markers.

12. The control system of claim 11, wherein multiple external measurement devices obtain position measurements of a single marker so as to provide location data from multiple perspectives.

13. The control system of claim 8, wherein the external measurement devices also monitor for objects that may enter the determined movement envelope and wherein the controller inhibits motion if any collision with such objects is indicated.

14. A method of registering and positioning a patient for delivery of therapy, the method comprising the steps of:

positioning a patient in an initial pose with a patient positioner, wherein the patient positioner is capable of movement in multiple translational and multiple rotational axes;

externally measuring the locations of selected points of the patient positioner and a movable therapy delivery assembly, wherein a movement envelope of the patient positioner and of the therapy delivery assembly intersect at least one of each other and other components proximate the patient positioner and the therapy delivery assembly;

determining a difference vector between the observed initial pose and a desired treatment pose with respect to the therapy delivery assembly;

determining a corresponding first movement command and a movement trajectory to bring the patient to the desired treatment pose with respect to the therapy delivery assembly; and

comparing the movement trajectory with the measured locations of the selected points prior to initiating a corresponding first movement and initiating the first movement by performing the indicated first movement command if no collision is indicated.

15. The method of claim 14, wherein externally measuring the location of the selected points comprises employing a plurality of cameras to obtain optical images of the selected points.

16. The method of claim 14, wherein the difference vector is determined in a first reference frame and wherein determining the movement commands comprises transforming the difference vector in the first reference frame into a corresponding movement vector in a second reference frame.

17. The method of claim 14, further comprising, prior to initiating movement, evaluating the externally measured locations and inhibiting movement and triggering a fault recovery state when an inconsistency or conflict is indicated in the externally measured locations.

18. The method of claim 14, further comprising obtaining radiographic image data of the patient and wherein the determining the movement vector and the corresponding movement commands is based at least in part on the obtaining radiographic data.

19. The method of claim 14, further comprising:

determining multiple direction vectors of the selected points;

determining intersections of the multiple direction vectors; and

determining rotational orientations such that the locations comprise both a translational and rotational dimension.

20. The method of claim 14, comprising externally measuring the locations of at least some of the selected points from multiple perspectives.

21. The method of claim 14, further comprising monitoring the movement trajectory for possible intrusion of foreign objects and inhibiting movement if such intrusion of foreign object occurs.