Radiation based treatment beam position calibration and verification
Inventors
Kilby, Warren • Jordan, Petr • Noll, John • Maurer, JR., Calvin
Assignees
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Publication Number
US-11648423-B2
Publication Date
2023-05-16
Expiration Date
Abstract
A phantom, calibration system and calibration method are described. The phantom having a phantom body and an X-ray luminescent material, wherein at least a portion of the X-ray luminescent material is on a surface of the phantom.
Core Innovation
The invention provides a method of calibration in a radiation delivery system that calibrates a position of a radiation source, including a radiation beam emitted by the radiation source, by using imaging of an X-ray luminescent phantom. A camera acquires an image of the radiation beam incident on the phantom, where the phantom comprises an X-ray luminescent material. The method identifies a pattern overlaid on the X-ray luminescent material and determines a beam pointing offset based on the image and the overlaid pattern.
The invention determines a relative position of the camera with respect to a beam axis of the radiation beam based on the pattern overlaid on the X-ray luminescent material. Using that relative position, it determines a relationship between a centroid of the phantom and a different centroid of the radiation beam incident on the pattern. A position of the radiation source is calibrated based on the beam pointing offset and the relationship between the centroid of the phantom and the different centroid of the radiation beam incident on the pattern.
In one verification aspect, the method further includes acquiring a second camera image after calibrating the position of the radiation source, calculating a beam pointing error based on the second image and the first image, and outputting the beam pointing error. In addition, the calibration workflow can include image sets that are acquired before irradiation for beam pointing offset determination.
Claims Coverage
The document provides two independent claims, covering both a calibration method and a calibration system. Across these claims, five inventive features are explicitly used to compute and apply beam pointing offset and a centroid relationship for calibrating the radiation source position, with an optional post-calibration beam pointing error calculation.
Camera-imaged X-ray luminescent phantom with overlaid pattern
Acquiring, using a camera, an image of a radiation beam incident on a phantom comprising an X-ray luminescent material, and identifying a pattern overlaid on the X-ray luminescent material.
Beam pointing offset determination from camera image
Determining a beam pointing offset based on the image.
Camera relative position to beam axis and centroid relationship
Determining, based on the pattern overlaid on the X-ray luminescent material, a relative position of the camera with respect to a beam axis of the radiation beam, and determining, based on the relative position, a relationship between a centroid of the phantom and a different centroid of the radiation beam incident on the pattern.
Calibrating radiation source position from beam pointing offset and centroid relationship
Calibrating a position of the radiation source of the radiation delivery system based on the beam pointing offset and the relationship between the centroid of the phantom and the different centroid of the radiation beam incident on the pattern.
Post-calibration beam pointing error based on second image
Acquiring a second camera image of the radiation beam incident on the phantom after calibrating the position of the radiation source, calculating a beam pointing error based on the second image and the first image, and outputting the beam pointing error.
Overall, the claim set centers on camera-acquired images of a radiation beam incident on an X-ray luminescent phantom with a pattern, deriving beam pointing offset, determining a camera-to-beam-axis relative position and a relationship between phantom and beam centroids, and using those results to calibrate the radiation source position, optionally followed by computing and outputting a beam pointing error from first versus second images.
Stated Advantages
Documented Applications
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