Radiation dosage monitoring system

Patent metadata

Field	Value
Publication number	US-9731150-B2
Application number	US-201615089494-A
Country	US
Kind code	B2
Filing date	Apr 2, 2016
Priority date	May 12, 2015
Publication date	Aug 15, 2017
Grant date	Aug 15, 2017

Abstract

Some embodiments are directed to a radiation dosage monitoring system including a model generation module configured to generate a 3D surface model of a portion of a patient undergoing radiation treatment, an image detector configured to detect Cherenkov radiation and any subsequent secondary and scattered radiation originating due to the initial Cherenkov radiation emitted from the patient, a processing module configured to determine estimations of radiation applied to the patient utilizing the images from the image detector and the 3D model, and to utilize the determined estimations of radiation applied to the patient together with data indicative of the orientation of a radiation beam inducing emission of the Cherenkov radiation at a time when the radiation beam was applied to generate a 3D internal representation of the location of the portions of a irradiated patient resulting in the emission of the Cherenkov radiation.

First claim

The invention claimed is:

1. A radiation dosage monitoring system for determining internal radiation dosages received by a patient undergoing radiation treatment comprising:
a stereoscopic camera operable to obtain stereoscopic images of a patient undergoing radiation treatment, the stereoscopic camera being operable to detect Cherenkov radiation and subsequent secondary and scattered radiation originating due to the initial Cherenkov radiation emitted from a surface of the patient when the patient is irradiated by a radiation beam;
a 3D position determination module operable to process stereoscopic images obtained by the stereoscopic camera to identify 3D positions of points on the surface of the patient undergoing radiation treatment by identifying corresponding points in pairs of images obtained by the stereoscopic camera and determining 3D positions for those points based on the relative positions of corresponding points in obtained pairs of images and stored data identifying the relative positions of cameras obtaining the images; a model generation module operable to process identified 3D position data generated by the 3D position determination module to generate a 3D wire mesh computer model of the surface of a portion of the patient undergoing radiation treatment; and
a processing module operable to determine estimations of internal radiation dosages received by internal portions of the patient by:
utilizing images of detected Cherenkov radiation emitted from a surface of the patient to texture render a generated model of a portion of the surface of the patient generated by the model generation module thereby generating a representation of the radiation applied to the surface of the patient; and
utilizing the texture rendered model together with data indicative of the orientation of a radiation beam at the time emission of Cherenkov radiation occurred and a model of the absorption of radiation by tissue in the portion of a patient being irradiated to determine estimations of radiation dosages received by internal portions of the patient.

2. A radiation dosage monitoring system according to claim 1 wherein the data indicative of the orientation of a radiation beam inducing emission of Cherenkov radiation comprises data determined from a radiotherapy treatment plan.

3. A radiation dosage monitoring system according to claim 1 wherein the stereoscopic camera is operable to monitor the position and orientation of a treatment apparatus relative to a patient being irradiated and the processing module is operable to determine the orientation of a radiation beam inducing emissions of Cherenkov radiation from the position and orientation of a treatment apparatus relative to the patient.

4. A radiation dosage monitoring system according to claim 1 wherein the processing module is operable to process images obtained by the stereoscopic camera to determine a representation of the radiation applied to the surface of the patient by:
obtaining a first image from the stereoscopic camera of the patient from a view point without radiation being applied to the patient;
obtaining a second image from the stereoscopic camera of a patient from the same viewpoint under the same lighting conditions as the first image with radiation being applied to the patient;
determining a difference image subtracting image values for pixels in the first image from corresponding pixel values in the second image; and
generating a representation of the radiation applied to the surface of a patient by utilizing the determined difference image to texture render a generated model of a portion of the surface of the patient.

5. A radiation dosage monitoring system according to claim 4 wherein the processing module is operable to process groups of images obtained by the stereoscopic camera for periods of time when the position and orientation of a radiation beam does not vary and determine a representation of the radiation applied to the surface of a patient by determining the sum of pixel values in difference images for corresponding pixels in a set of images a patient from the same viewpoint under the same lighting conditions as the first image with radiation being applied to the patient.

6. A radiation dosage monitoring system according to claim 5 wherein the processing module is operable to process images in a set of images a patient from the same viewpoint under the same lighting conditions as the first image with radiation being applied to the patient to identify saturated pixels or pixel values corresponding to statistical outliers appearing in images which do not appear in a successive image; wherein such saturated pixel values are not utilized to determine a representation of the radiation applied to the surface of a patient.

7. A radiation dosage monitoring system according to claim 1 wherein the processing module operable to process the images obtained by the stereoscopic camera utilizes data indicative of chromophores present in a patient's skin to apply a correction factor to such images to account for absorption of Cherenkov radiation by chromophores in the skin when utilizing the images to generate a representation of radiation applied to the surface of the patient.

8. A radiation dosage monitoring system according to claim 7 wherein the processing module is operable to process images by:
obtaining a first image from the stereoscopic camera of the patient from a viewpoint without radiation being applied to the patient;
obtaining a second image from the stereoscopic camera of a patient from the same viewpoint under the same lighting conditions as the first image with radiation being applied to the patient; and
determining a difference image subtracting image values for pixels in the first image from corresponding pixel values in the second image.

9. A radiation dosage monitoring system according to claim 8 wherein the processing module is operable to process groups of images camera for periods of time when the position and orientation of a radiation beam does not vary by determining the sum of pixel values in difference images for corresponding pixels in a set of images of a patient in the same position from the same viewpoint under the same lighting conditions as the first image with radiation being applied to the patient.

10. A radiation dosage monitoring system according to claim 9 wherein the processing module is operable to process images to identify saturated pixels or pixel values corresponding to statistical outliers appearing in images which do not appear in a successive image; wherein such saturated pixel values are not utilized to determine a representation of the location of the portions of a patient irradiated by radiation resulting in the emission of the Cherenkov radiation.

11. A radiation dosage monitoring system according to claim 7 wherein the processing module is operable to process images obtained by the stereoscopic camera to determine data indicative of chromophores present in a patient's skin and processing module is operable to convert said processed images into images representative of radiation skin dosage by modifying pixel values in accordance with a correction factor to account of the absorption of Cherenkov radiation and any subsequent secondary and scattered radiation originating due the initial Cherenkov radiation by chromophores present in a patient's skin.

12. A radiation dosage monitoring system according to claim 7 wherein the data indicative of chromophores present in a patient's skin comprises a visual estimation of the skin color of the patient based on a comparison with a reference set of skin tones and the correction factor applied is determined on the basi

Assignees

• Vision Rt Ltd

Inventors

• Hale Gideon Matthew
• Meir Ivan Daniel
• Pawlicki Todd
• Allen Martin

Classifications

• G06T7/0012

  Biomedical image inspection · CPC title

• A61N5/1075

  for testing, calibrating, or quality assurance of the radiation treatment apparatus · CPC title

• A61N2005/1059

  using cameras imaging the patient · CPC title

• A61N2005/1072

  taking into account movement of the target · CPC title

• G06T2207/30244

  Camera pose · CPC title