Proton scattering analysis system

• US 9,084,887 B2
• Filed: 01/20/2014
• Issued: 07/21/2015
• Est. Priority Date: 02/05/2009
• Status: Active Grant

• Current Assignee: LOMA Linda University Medical Center (Mission Healthcare Services LLC)
• Original Assignee: LOMA Linda University Medical Center (Mission Healthcare Services LLC)
• Inventors: Schulte, Reinhard W., Bashkirov, Vladimir A.
• Primary Examiner(s): Matthews, Christine H
• Assistant Examiner(s): LANNU, JOSHUA DARYL DEANON
• Application Number:
  US14/159,259
• Publication Number:
  US 20140200448A1
• Time in Patent Office: 547 Days
• US Class Current: 1/1
• CPC Class Codes: A61B 6/54 Control of apparatus or devices for radiation diagnosis
• CPC Class Codes: A61N 2005/1087 Ions; Protons
• CPC Class Codes: A61N 5/103 Treatment planning systems
• CPC Class Codes: A61N 5/1048 Monitoring, verifying, controlling systems and methods
• CPC Class Codes: A61N 5/1071 for verifying the dose delivered by the treatment plan
• CPC Class Codes: G01N 23/02 by transmitting the radiation through the material

Abstract

Disclosed are systems and methods for characterizing interactions or proton beams in tissues. In certain embodiments, charged particles emitted during passage of protons, such as those used for therapeutic and/or imaging purposes, can be detected at relatively large angles. In situations where beam intensity is relatively low, such as in certain imaging applications, characterization of the proton beam with charged particles can provide sufficient statistics for meaningful results while avoiding the beam itself. In situations where beam intensity is relatively high, such as in certain therapeutic applications, characterization of the proton beam with scattered primary protons and secondary protons can provide information such as differences in densities encountered by the beam as it traverses the tissue and dose deposited along the beam path. In certain situations, such beam characterizations can facilitate more accurate planning and monitoring of proton-based therapy.

Claims

1. A proton scattering analysis system comprising:

a support device configured to support a volume of tissue and expose at least a portion of the volume of tissue to a beam of protons, the beam of protons configured for therapeutic treatment of at least a portion of the volume of tissue, the beam of protons defining a beam axis extending through the volume of tissue;

a charged particle detector disposed outside of the beam axis and configured so as to detect charged particles resulting from interactions of the beam of protons with the volume of tissue, the charged particle detector configured to detect charged particles scattered from the volume of tissue at an angle relative to the beam axis, the angle being within a range of approximately 20 degrees to 90 degrees, the charged particle detector configured to facilitate reconstruction of tracks associated with the detected charged particles, the detection resulting in generation of signals; and

a computing device in communication with the charged particle detector;

the computing device configured to receive the signals and to generate data having information that allows the reconstruction of the tracks so as to allow estimation of locations of the interactions in the volume of tissue.

2. The system of claim 1, wherein the angle is within a range of approximately 25 degrees to 70 degrees.

3. The system of claim 2, wherein the angle is within a range of approximately 30 degrees to 60 degrees.

4. The system of claim 3, wherein the angle is approximately 45 degrees.

5. The system of claim 1, wherein the beam of protons has an average kinetic energy in a range of approximately 45 MeV to 300 MeV.

6. The system of claim 5, wherein the beam of protons has an average kinetic energy in a range of approximately 80 MeV to 270 MeV.

7. The system of claim 6, wherein the beam of protons has an average kinetic energy of approximately 100 MeV.

8. The system of claim 7, wherein the beam of protons is configured for cancer therapy based on Bragg peak effect.

9. The system of claim 6, wherein the beam of protons has an average kinetic energy of approximately 250 MeV.

10. The system of claim 9, wherein the beam of protons is configured for radiosurgery application based on ionization by the protons.

11. A proton based imaging and therapy system comprising:

a proton source for generating a beam of protons;

a proton delivery device configured to deliver the proton beam down a beam path defining a beam axis, the proton beam configurable for a therapy mode and an imaging mode;

a support device configured to support a patient and to position the patient so that at least a portion of the patient intersects the beam axis,

a charged particle detector mounted to a mounting mechanism and configured to position the detector at first and second positions relative to the beam axis, the first position being downstream of the patient along the beam axis, the second position being outside of the beam path at an angle with respect to the beam axis, the angle within a range of approximately 20 to 90 degrees, the detector configured to detect charged particles resulting from interactions of the beam of protons with the patient; and

a control system, configured to position the detector at the first position and to deliver the beam of protons in the imaging mode when the proton based imaging and therapy system is being operated for imaging purposes, and to position the detector at the second position and to deliver the beam of protons in the therapy mode when the proton based imaging and therapy system is being operated for therapy purposes,

wherein in the second position, the charged particle detector is configured to detect charged particles that are scattered at the angle with respect to the beam axis.

12. A proton therapy system for delivery of a therapeutic proton beam comprising a plurality of protons towards a target region of a patient, the proton therapy system comprising:

a patient support configured for supporting a patient;

a proton source for generating a therapeutic proton beam;

a proton delivery device configured to receive the therapeutic proton beam from the proton source and direct the therapeutic proton beam at a mean initial energy along an initial path towards a target region of the patient supported on the patient support, wherein respective paths of at least some of the protons of the therapeutic proton beam are deflected in response to contact with the patient;

at least one sensor arranged proximal the target region and configured to measure at least one of an impact location of incident protons and an impact energy of incident protons; and

a processor in communication with the at least one sensor and configured to calculate at least one of an amount of deflection of the incident protons from the initial path and an incident energy loss from the mean initial proton energy and to provide an indication of at least one of an electron density within the target region through which the protons pass and an atomic number corresponding to the target region.

13. The system of claim 12, wherein the at least one sensor comprises one or both of silicon strip detectors and a proton calorimeter.

14. The system of claim 12, comprising a plurality of sensors and wherein the sensors are arranged substantially symmetrically around the target region.

15. The system of claim 12, wherein the at least one sensor is arranged asymmetrically about the target region.

16. The system of claim 12, wherein the at least one sensor and the proton beam source are arranged to rotate about the target region.

17. A method for planning a proton therapy, the method comprising:

positioning, a patient on a support device so as to allow exposure of a portion of the patient to a beam of protons, the beam of protons configured for therapeutic treatment and travelling generally along a beam path within the patient;

delivering one or more spills of protons to the patient, each spill of protons having an intensity associated with the therapeutic beam of protons;

detecting primary and secondary protons with a particle detector positioned at an angle relative to the beam path, the angle being within a range of approximately 20 degrees to 90 degrees;

determining a profile of the beam path based at least in part on data measured with the particle detector, the measured data related to interaction of the one or more spills of protons in the patient, the profile comprising scattering locations of the primary protons associated with the one or more spills of protons and vertex locations of the secondary protons emitted from within the patient, the profile providing information about differences in densities along the beam path; and

adjusting the beam based on the determined profile.

18. The method of claim 17, wherein the determination of the profile is performed while delivery of the one or more spills of protons to the patient is halted.

19. The method of claim 17, wherein the differences in densities include differences in densities of a tumor and healthy tissue.