Feature tracking using ultrasound

• US 9,248,316 B2
• Filed: 09/22/2011
• Issued: 02/02/2016
• Est. Priority Date: 01/12/2010
• Status: Active Grant

• Current Assignee: Elekta Ltd. (Elekta AB)
• Original Assignee: Elekta Ltd. (Elekta AB)
• Inventors: Lachaine, Martin, Tremblay, Sebastien, Lathuiliere, Fabienne, Falco, Tony
• Primary Examiner(s): CHAO, ELMER M
• Application Number:
  US13/239,795
• Publication Number:
  US 20120071758A1
• Time in Patent Office: 1,594 Days
• Field of Search: 600437-458
• US Class Current: 1/1
• CPC Class Codes: A61B 2034/2055 Optical tracking systems
• CPC Class Codes: A61B 2034/2063 Acoustic tracking systems, e.g. using ultrasound
• CPC Class Codes: A61B 2034/2065 Tracking using image or pattern recognition
• CPC Class Codes: A61B 2090/378 using ultrasound
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61B 8/085 for locating body or organic structures, e.g. tumours, calculi, blood vessels, nodules
• CPC Class Codes: A61B 8/4245 involving determining the position of the probe, e.g. with respect to an external reference frame or to the patient
• CPC Class Codes: A61B 8/4263 using sensors not mounted on the probe, e.g. mounted on an external reference frame
• CPC Class Codes: A61B 8/4461 Features of the scanning mechanism, e.g. for moving the transducer within the housing of the probe
• CPC Class Codes: A61B 8/483 involving the acquisition of a 3D volume of data
• CPC Class Codes: A61B 8/58 Testing, adjusting or calibrating the diagnostic device
• CPC Class Codes: A61B 8/587 Calibration phantoms models for medical purposes G09B23/28
• CPC Class Codes: A61N 2005/1058 using ultrasound imaging
• CPC Class Codes: A61N 5/1049 for verifying the position of the patient with respect to the radiation beam
• CPC Class Codes: G06T 2207/10132 Ultrasound image
• CPC Class Codes: G06T 7/248 involving reference images or patches

Abstract

Various implementations of the invention provide techniques and supporting systems that facilitate real-time or near-real-time ultrasound tracking for the purpose of calculating changes in anatomical features during a medical procedure. More specifically, anatomical features within a patient undergoing a medical procedure are tracked by obtaining temporally-distinct three dimensional ultrasound images that include the feature of interest and obtaining a targeted subset of ultrasound images focused on the feature. Based on the targeted subset of ultrasound images, a displacement of the feature is determined and image parameters used to obtain the targeted subset of ultrasound images are adjusted based on the displacement. This results in a time-based sequence of three dimensional images and targeted ultrasound images of the feature that identify changes in the position, size, location, and/or shape of the feature.

Claims

1. A computer-implemented method utilizing a processor executing computer-executable instructions for tracking an anatomical feature of interest using an imaging device, the method comprising:

receiving a series of three dimensional images of a region of interest acquired by the imaging device at a first image acquisition rate, wherein the region of interest includes the anatomical feature of interest;

determining, by the processor, a location of the anatomical feature of interest in the region of interest;

receiving temporally-displaced targeted subsets of ultrasound images acquired by the imaging device at a second image acquisition rate greater than the first image acquisition rate for the determined location;

comparing, by the processor, each targeted subset with at least one of the three dimensional images;

determining, by the processor, a displacement of the anatomical feature based on each comparison; and

using the determined displacement to determine whether to modify a radiation therapy treatment plan.

2. The computer-implemented method of claim 1, further comprising:

determining if the displacement of the anatomical feature exceeds a displacement threshold; and

obtaining an updated three dimensional image of the region of interest according to the first image acquisition rate prior to a scheduled update.

3. The computer-implemented method of claim 2, wherein the displacement threshold comprises an upper limit of the anatomical feature of interest.

4. The computer-implemented method of claim 1, further comprising:

determining if the displacement exceeds a safety threshold; and

causing a medical procedure to stop to allow for an adjustment.

5. The computer-implemented method of claim 1, further comprising adjusting one or more image parameters used in obtaining the targeted subsets of images based on the displacement.

6. The computer-implemented method of claim 1, further comprising adjusting at least one of a treatment couch, a multi-leaf collimator, or a combination thereof in response to the displacement during treatment of the anatomical feature.

7. The computer-implemented method of claim 1, wherein the targeted subset comprises a plurality of two dimensional image slices of the anatomical feature.

8. The computer-implemented method of claim 1, wherein the targeted subset comprises two or more tracking planes having two-dimensional images of the region of interest.

9. The computer-implemented method of claim 8, wherein one or more of the tracking planes comprise at least one reconstructed plane including a voxel set attached to a single plane that passes through the region of interest.

10. The computer-implemented method of claim 8, wherein the one or more tracking planes comprise a first tracking plane that is orthogonal to a second tracking plane, wherein the first tracking plane and the second tracking plane include two-dimensional images of the region of interest.

11. The computer-implemented method of claim 1, wherein the targeted subset further comprises a plurality of three dimensional datasets related to a limited region of interest.

12. The computer-implemented method of claim 11, wherein the limited region of interest is based at least in part on an adjusted sector size parameter.

13. The computer-implemented method of claim 11, wherein the limited region of interest is based at least in part on an adjusted image depth parameter.

14. The computer-implemented method of claim 11, wherein the limited region of interest is based at least in part on an adjusted ultrasound sector angle.

15. The computer-implemented method of claim 1, wherein obtaining the targeted subsets at the second image acquisition rate greater than the first image acquisition rate, further comprises obtaining three dimensional datasets having a reduced image resolution.

16. The computer-implemented method of claim 1, further comprising obtaining the three dimensional images using at least one of a motorized probe, a biplanar probe, and a matrix probe associated with the imaging device.

17. The computer-implemented method of claim 1, wherein a fiducial is embedded in the anatomical feature, and wherein comparing each subset with at least one of the three dimensional images further comprises comparing images of the fiducial in the subset and the at least one of the three dimensional images.

18. The computer-implemented method of claim 1, wherein the anatomical features of a patient comprises at least one of a target lesion, one or more subsets of the target lesion, or a fiducial.

19. The computer-implemented method of claim 1, wherein modifying the radiation therapy treatment plan is based on a registration algorithm using the displacement to determine changes in the anatomical feature.

20. The computer-implemented method of claim 19, wherein the displacement is determined from a partially updated image.

21. The computer-implemented method of claim 1, wherein the radiation therapy treatment plan is modified in real-time.

22. The computer-implemented method of claim 1, wherein the displacement is a positional displacement determined in real-time.