Dynamic radiation therapy simulation system

• US 20060291621A1
• Filed: 06/22/2005
• Published: 12/28/2006
• Est. Priority Date: 06/22/2005
• Status: Active Grant

• Current Assignee: The Board of Trustees of the University of Arkansas (University of Arkansas System)
• Original Assignee: The Board of Trustees of the University of Arkansas (University of Arkansas System)
• Inventors: Ratanatharathorn, Vaneerat, Weng, Xuejun, Yan, Yulong, Penagaricano, Jose
• Granted Patent: US 7,349,522 B2
• Time in Patent Office: Days
• US Class Current: 378/65
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 6/541 involving acquisition triggered by a physiological signal
• 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 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: G01N 2223/076 X-ray fluorescence
• CPC Class Codes: G01N 23/223 by irradiating the sample with X-rays or gamma-rays and by measuring X-ray fluorescence

Abstract

A system for dynamic treatment simulation for radiotherapy. Software is implemented on a computer system to perform dynamic simulation by displaying every segment of dynamic treatment beams on top of real-time fluoroscopic image sequences. Automated distortion correction of the fluoroscopic image due to the image intensifier is performed in real-time. A respiration phase indicator measures changes in circumference of the patient'"'"'s chest through the movement of a radio-opaque marker that appears directly in the fluoroscopic images of the patient.

Claims

1. A method for dynamic radiation therapy simulation of a treatment plan for a patient, comprising the steps of:

storing on a computer readable medium a set of reference images of the patient,

planning a multi-leaf collimator plan for dynamic radiation therapy for the patient comprising a sequence of plan images and storing said plan images on a computer readable medium;

acquiring a sequence of real-time fluoroscopic images of the patient over at least one respiration cycle of the patient;

correcting image intensifier distortion of said fluoroscopic images in real-time;

displaying the plan or references images overlying the fluoroscopic images in real-time.

2. The method of claim 1 wherein a respiration cycle indicator indicates the respiratory cycle by changes in the circumference of the patient'"'"'s chest.

3. The method of claim 2 wherein said respiration cycle indicator comprises a belt for encircling the patient'"'"'s chest, said belt having an elastic portion extending between a first point and a second point on said belt;

a tube having a first end in a fixed relationship to said first point;

a flexible wire having a first end affixed to said second point, said wire passing through said tube and extending beyond a second end of said tube;

a radio-opaque marker attached to a second end of said flexible wire whereby changes in circumference of the patient'"'"'s chest effect a linear translation of said marker.

4. The method of claim 3 where said radio-opaque marker is imaged in said real-time fluoroscopic images.

5. The method of claim 4 where said plan images are gated to the respiratory cycle indicated by the radio-opaque marker.

6. The method of claim 1 where the step of correcting distortion of said fluoroscopic images in real-time comprises the steps of:

compiling a library of correction models of image distortion for a plurality of image intensifier positions,

capturing the position of the image intensifier for a fluoroscopic image;

interpolating among adjacent image intensifier positions and calculating an interpolated correction model;

preparing a two-dimensional indexing buffer from the interpolated correction model whereby each point in a corrected image is indexed to a point in the uncorrected image; and

preparing a corrected image by selecting each corrected point from the uncorrected image as indexed by the indexing buffer.