Apparatus for irradiating a target volume

• US 7,307,264 B2
• Filed: 11/29/2002
• Issued: 12/11/2007
• Est. Priority Date: 05/31/2002
• Status: Expired due to Fees

• Current Assignee: Ion Beam Applications s.a.
• Original Assignee: Ion Beam Applications s.a.
• Inventors: Brusasco, Caterina, Prieels, Damien, Marchand, Bruno, De Le Hoye, Jean-François
• Primary Examiner(s): Wells; Nikita
• Assistant Examiner(s): Smith, II; Johnnie L
• Application Number:
  US10/513,544
• Publication Number:
  US 20050238134A1
• Time in Patent Office: 1,838 Days
• Field of Search: 430/296, 430/30, 430/312, 250/492.2, 250/492.22
• US Class Current: 250/492.22
• CPC Class Codes: A61N 2005/1087 Ions; Protons
• CPC Class Codes: A61N 5/10 X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy A61N5/01 takes precedence
• CPC Class Codes: A61N 5/1043 Scanning the radiation beam, e.g. spot scanning or raster scanning
• CPC Class Codes: A61N 5/1048 Monitoring, verifying, controlling systems and methods
• CPC Class Codes: G21K 1/087 by electrical means

Abstract

An irradiation apparatus for irradiating by scanning a target volume according to a predetermined dose profile with a scanning beam of charged particles forming an irradiation spot on said target volume, said apparatus comprising:

• • a beam generating device,
  • a reference generator for computing, from said predetermined dose profile, through a dynamic inverse control strategy, the time evolution of commanded variables, these variables being the beam current I(t), the spot position settings x(t),y(t) and the scanning speed settings v_x(t), v_y(t),
  • a monitor device having means for detecting at each time (t), the actual spot position as a measured position defined by the values x_m(t),y_m(t) on the target volume,
    characterised in that said irradiation apparatus further comprises means for determining the differences e_x(t), e_y(t) between the measured values x_m(t), y_m(t) and the spot position settings x(t) and y(t), and means for applying a correction to the scanning speed settings v_x(t) and v_y(t) depending on said differences e_x(t), e_y(t). The present invention is also related to a monitor for determining beam position in real-time.

Claims

1. An irradiation apparatus for irradiating by scanning a target volume according to a predetermined dose profile with a scanning beam of charged particles forming an irradiation spot on said target volume, said apparatus comprising:

a beam generating device,

a reference generator for computing, from said predetermined dose profile, through a dynamic inverse control strategy, the time evolution of commanded variables, these variables being the beam current I(t), the spot position settings x(t),y(t) and the scanning speed settings v_x(t), v_y(t),

a monitor device having means for detecting at each time (t), the actual spot position as a measured position defined by the values x_m(t),y_m(t) on the target volume,

wherein said irradiation apparatus further comprises means for determining the differences e_x(t), e_y(t) between the measured values x_m(t), y_m(t) and the spot position settings x(t) and y(t), and means for applying a correction to the scanning speed settings v_x(t) and v_y(t) depending on said differences e_x(t), e_y(t).

2. The irradiation apparatus according to claim 1, wherein the monitor device further comprises means for measuring the total instantaneous dose deposited by the beam in the target volume, and means for correcting this dose deposition or for pausing the beam and informing an external operator when said instantaneous dose is outside of an expected range.

3. The irradiation apparatus according to claim 1, arranged so as to generate a beam in one direction and so as to irradiate with said beam the target volume in layers perpendicular to said direction, said layers being irradiated in one or more irradiation frames, wherein the monitor device comprises in addition means for determining the dose distribution in a plane perpendicular to the beam direction, for each successive irradiation frame, and means for pausing the beam and informing an external operator when said dose distribution is outside of an expected range.

4. A process implementing the apparatus as claimed in claim 1, said process comprising the steps of:

determining a dose distribution profile referenced as a map D(x,y,z);

determining, from said dose map, trajectories comprising spot position settings x(t), y(t), scanning speed settings v_x(t), v_y(t) and a beam current setting I(t) for a set of irradiation depths z;

feeding said scanning speed signals v_x(t) and v_y(t) to a scanning magnet system;

feeding said beam current signal I(t) to a beam generating device;

detecting and measuring the actual spot values x_m(t), y_m(t), determining the differences e_x(t), e_y(t) between said measured spot values x_m(t), y_m(t) and the spot position settings x(t) and y(t); and

applying a correction to the scanning speed settings v_x(t) and v_y(t) depending on said differences e_x(t), e_y(t).

5. Use of the apparatus according to claim 1 or a process implementing the apparatus as claimed in claim 1, said process comprising the steps of:

determining a dose distribution profile referenced as a map D(x,y,z);

determining, from said dose map, trajectories comprising spot position settings x(t), y(t),

determining, from said dose map, trajectories comprising spot position settings x(t), v(t), scanning speed settings v_x(t), v_yt and a beam current setting I(t) for a set of irradiation depths z;

feeding said scanning speed signals v_x(t) and v_y(t) to a scanning magnet system;

feeding said beam current signal I(t) to a beam generating device;

detecting and measuring the actual spot values x_m(t), y_m(t),

determining the differences e_x(t), e_y(t) between said measured spot values x_m(t), y_m(t) and the spot position settings x(t) and v(t); and

applying a correction to the scanning speed settings v_x(t) and v_y(t) depending on said differences e_x(t), e_y(t) for irradiating a target.