System for the delivery of proton therapy by pencil beam scanning of a predeterminable volume within a patient

• US 9,108,050 B2
• Filed: 03/28/2013
• Issued: 08/18/2015
• Est. Priority Date: 04/03/2012
• Status: Active Grant

• Current Assignee: Paul Scherrer-Institut (Schweizerische Eidgenossenschaft)
• Original Assignee: Paul Scherrer-Institut (Schweizerische Eidgenossenschaft)
• Inventors: Bula, Christian, Meer, David, Pedroni, Eros
• Primary Examiner(s): Souw, Bernard E
• Application Number:
  US14/390,472
• Publication Number:
  US 20150099917A1
• Time in Patent Office: 873 Days
• Field of Search: 250/491.1, 250/492.1, 250/492.3, 250/493.1, 250/505.1, 250/526, 315501-505, 315/507, 315/111.81
• US Class Current: 1/1
• CPC Class Codes: A61N 2005/1074 Details of the control system, e.g. user interfaces
• CPC Class Codes: A61N 2005/1087 Ions; Protons
• CPC Class Codes: A61N 5/1044 with multiple repetitions of the scanning pattern
• CPC Class Codes: A61N 5/1067 in real time, i.e. during treatment
• CPC Class Codes: A61N 5/1075 for testing, calibrating, or quality assurance of the radiation treatment apparatus

Abstract

A system and a method improve a quality of beam delivery in proton therapy by pencil beam scanning of a predeterminable volume within a patient that minimizes beam position errors. The system has a proton source generating a proton beam, a number of proton beam bending/focusing units, a beam nozzle having an outlet for the proton beam to penetrate the predetermined volume, a beam bending magnet, and a couple of sweeper magnets to sweep the proton beam in both lateral directions. A position-sensitive detector is aligned with the nozzle to control the position of the proton beam and control logic controls the position and the energy of the proton beam and has a beam steering data set. A correction logic is aligned with the control logic for correcting beam position errors by comparing an expected beam position with the actual beam position detected and generates beam position correction data.

Claims

1. A system for delivery of proton therapy by pencil beam scanning of a predeterminable volume within a patient, the system comprising:

a proton source for generating a proton beam being adjustable with respect to beam intensity, beam energy or the beam intensity and the beam energy;

a number of proton beam bending and/or focusing units;

a beam nozzle having an outlet for the proton beam to penetrate the predeterminable volume of the patient;

a beam bending magnet disposed upstream of said beam nozzle;

a plurality of sweeper magnets for sweeping the proton beam in both lateral directions;

a first position-sensitive detector aligned with said beam nozzle for controlling a position of the proton beam;

a second position-sensitive detector integrated into a patient table;

control logic for controlling the position and energy of the proton beam and having a beam steering data set; and

correction logic aligned with said control logic for correcting beam position errors by comparing an expected beam position with an actual beam position detected in said first position-sensitive detector and generating beam position correction data in dependency on comparison results, the beam position correction data is introduced into the beam steering data set after running a patient-field specific steering file to identify scan specific corrections, and wherein said correction logic further uses a generic dynamic correction model for correcting the beam position errors which decay as a function of time after a change of proton energy.

2. The system according to claim 1, wherein said correction logic has automated software for feeding back the beam position correction data derived from comparison data logged from a test irradiation for verification of a therapy-specific beam steering data set into an improved new version of the beam steering data set of the test irradiation which is then qualified to be used for treating the patient in at least one subsequent irradiation.

3. The system according to claim 1, wherein said second position-sensitive detector is disposed in an iso-center of proton beam geometrics.

4. The system according to claim 1, further comprising a degrader for adjusting the proton beam with respect to the beam intensity and the beam energy.

5. A method for improving quality of beam delivery in a system for a delivery of proton therapy by pencil beam scanning of a predeterminable volume within a patient, which comprises the steps of:

providing a proton source for generating a proton beam being adjustable with respect to a beam intensity, beam energy or the beam intensity and the beam energy;

providing a number of proton beam bending and/or focusing units for generating a beam line;

providing a beam nozzle having an outlet for the proton beam to penetrate the predeterminable volume of the patient;

providing a beam bending magnet disposed upstream of the beam nozzle;

providing a couple of sweeper magnets for sweeping the proton beam in both lateral directions;

providing a position-sensitive detector aligned with the beam nozzle for controlling a position of the proton beam;

integrating a further position-sensitive detector into a patient table;

providing control logic for controlling the position and energy of the proton beam by using a beam steering data set;

providing correction logic aligned with the control logic for correcting beam position errors by comparing an expected beam position with an actual beam position detected in the position-sensitive detector; and

generating beam position correction data in dependency of comparison results, wherein the beam position correction data is introduced into the beam steering data set after running a patient-field specific steering file for identifying scan specific corrections, and wherein the correction logic further uses a generic dynamic correction model for correcting the beam position errors which decay as a function of time after a change of proton energy.

6. The method according to claim 5, wherein the correction logic has automated software for feeding back the beam position correction data derived from comparison data logged from a patient-related test irradiation for verification of an therapy-specific beam steering data set into an improved new version of the beam steering data set of the patient-related test irradiation which is then qualified to be used for treating the patient in at least one subsequent irradiation.

7. The method according to claim 5, which further comprises disposing the further position-sensitive detector in an iso-center of proton beam geometrics.

8. The method according to claim 5, which further comprises providing a degrader for adjusting the proton beam with respect to the beam intensity, the beam energy or the beam intensity and the beam energy.