METHODS AND SYSTEMS FOR COMPENSATING FOR CHANGES IN ANATOMY OF RADIOTHERAPY PATIENTS

• US 20090022383A1
• Filed: 07/21/2008
• Published: 01/22/2009
• Est. Priority Date: 07/20/2007
• Status: Active Grant

• Current Assignee: Elekta Ltd. (Elekta AB)
• Original Assignee: Elekta Ltd. (Elekta AB)
• Inventors: Falco, Tony, Lachaine, Martin
• Granted Patent: US 8,249,317 B2
• Time in Patent Office: Days
• US Class Current: 382/131
• CPC Class Codes: A61B 6/583 using calibration phantoms
• CPC Class Codes: A61N 2005/1054 using a portal imaging system
• 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: A61N 5/1065 Beam adjustment
• CPC Class Codes: G06T 2207/10072 Tomographic images
• CPC Class Codes: G06T 2207/10116 X-ray image
• CPC Class Codes: G06T 2207/30004 Biomedical image processing
• CPC Class Codes: G06T 7/30 Determination of transform parameters for the alignment of images, i.e. image registration

Abstract

Portal images are combined with 3D ultrasound to determine adjustments to patient treatment parameters. The images are acquired while the patient is in an initial position, and the images are registered to a treatment coordinate system. The images are combined and outlines of anatomical structures are superimposed on the portal images, resulting in new portal images that incorporate the anatomy extracted from the ultrasound. The enhanced portal images are used to identify modifications to the treatment parameters.

Claims

1. A method of modifying treatment parameters for a patient undergoing radiotherapy, the method comprising the steps of:

(a) establishing a set of baseline treatment parameters;

(b) during a treatment session obtaining, using different imaging modalities, at least two registered images of an anatomical region to be treated wherein at least some of the images are portal images from at least one beam direction, and at least one of the images is a non-x-ray-based 3D image;

(c) registering the at least two images to a coordinate system associated with a treatment device;

(d) segmenting the non-x-ray-based 3D image to form a 3D surface;

(e) projecting the surface onto the plane of each portal image;

(f) enhancing the portal images with data from the projected surface; and

(g) modifying the baseline treatment parameters based on the registered images.

2. A system for identifying changes to patient treatment parameters, the system comprising:

(a) a first register for storing a set of baseline treatment parameters;

(b) a second register for storing at least two images of an anatomical region to be treated, each image being obtained using different imaging modalities wherein at least some of the images are portal images from at least one beam direction, and at least one of the images is a non-x-ray-based 3D image; and

(c) a processor configured to;

(i) register the at least two images to a coordinate system associated with a treatment device;

(ii) segment the non-x-ray-based 3D image to form a 3D surface;

(iii) project the surface onto the plane of each portal image;

(iv) enhancing the portal images with data from the projected surface; and

(ii) determine modifications to the baseline treatment parameters based on the registered images.

3. The system of claim 2 further comprising a controller for affecting the modifications based on the modified treatment parameters.

4. The system of claim 2 wherein the modifications comprise positional changes to the patient.