System for the Delivery of Proton Therapy

• US 20080023644A1
• Filed: 02/19/2005
• Published: 01/31/2008
• Est. Priority Date: 04/27/2004
• Status: Active Grant

• Current Assignee: Paul Scherrer-Institut (Schweizerische Eidgenossenschaft)
• Original Assignee: Paul Scherrer-Institut (Schweizerische Eidgenossenschaft)
• Inventors: Pedroni, Eros
• Granted Patent: US 7,560,715 B2
• Time in Patent Office: Days
• US Class Current: 250/400
• CPC Class Codes: A61N 2005/1087 Ions; Protons
• CPC Class Codes: A61N 2005/1095 Elements inserted into the radiation path within the system, e.g. filters or wedges
• 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: G21K 1/093 by magnetic means
• CPC Class Codes: G21K 5/04 with beam-forming means
• CPC Class Codes: H05H 7/00 Details of devices of the types covered by groups H05H9/00, H05H11/00, H05H13/00

Abstract

A process for an intensity-modulated proton therapy of a predetermined volume within an object includes discretising the predetermined volume into a number of iso-energy layers each corresponding to a determined energy of the proton beam. A final target dose distribution is determined for each iso-energy layer. The final target dose distribution or at least a predetermined part of this final target dose distribution is applied by parallel beam scanning by controlling the respective beam sweepers, thereby scanning one iso-energy layer after the other using an intensity-modulated proton beam while scanning a predetermined iso-energy layer.

Claims

1. A system for an intensity-modulated proton therapy of a predetermined volume within an object, comprising:

a) a proton source in order to generate a proton beam being adjustable with respect to beam intensity;

b) a degrader being optionally disposable in the proton beam in order to attenuate the energy of the protons in the proton beam to a desired proton energy in the proton beam;

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

d) a beam nozzle having an outlet for the proton beam to penetrate the predetermined volume of the object;

e) a beam bending magnet being disposed upstream of the nozzles; and

f) a couple of sweeper magnets being disposed upstream of said beam bending magnet in order to sweep the proton beam in both lateral directions before the proton beam enters into the beam bending magnet,

g) said beam nozzle is defining a cross-sectional scanning area substantially perpendicular to the proton beam in a range of 10 to 30 cm², and

h) said sweeper magnets and said beam bending magnet are controlled in order to guarantee a parallel beam orientation over the complete cross-sectional scanning areas.

2. The system according to claim 1, wherein

a preabsorber body is optionally disposable between the outlet of the nozzle and the object.

3. The system according to claim 1,

wherein

the cross-sectional scanning area is oriented substantially perpendicular to a longitudinal axis of the proton beam, and a moving mechanism for the preabsorber body is provided which is remotely controllable in order to move the preabsorber body from a parking position into an absorbing position whereby covering the complete scanning area;

and vice versa.

4. The system according to claim 2, wherein

the preabsorber body comprises at least one of carbon and beryllium.

5. The system according to claim 1,

wherein

said beam bending magnet delivers a substantially 1:

1 image of the proton beam before entering into the beam bending magnet as compared to the beam image after the bending.

6. The system according to claim 1,

wherein

collimator is optionally pivoted into the proton beam upstream of the beam bending magnet;

said collimator being movable at least one of radially and azimuthally.

7. The system according to claim 1,

wherein the object is supported by a table which is optionally movable in a plane being substantially perpendicular to the proton beam by a table driving unit, whereby the movement of the table is detected by the table driving unit in order to control a deflection the proton beam in the respective sweeper magnet for annihilating a relative shift between the object and the proton beam during dose painting.

8. A process for an intensity-modulated proton therapy of a predetermined volume within an object;

comprising the steps of;

a) discretising the predetermined volume into a number of iso-energy layers each corresponding to a determined energy of the proton beam;

b) determining a final target dose distribution for each iso-energy layer; and

c) applying the final target dose distribution or at least a predetermined part of this final target dose distribution by parallel beam scanning by controlling the respective beam sweepers, thereby scanning one iso-energy layer after the other using an intensity-modulated proton beam while scanning a predetermined iso-energy layer.

9. The process according to claim 8,

wherein

the final target dose distribution is achieved by a multiple painting of the respective iso-energy layers, thereby each painting delivers a predetermined part of this final target dose distribution.

10. The process according to claim 8,

wherein

a geometrical field patching technique is used by moving a support table continuously, thereby simultaneously compensating the displacement of the motion of the support table with an offset applied to the beam sweepers.

11. The process according claim 8,

wherein

the magnetic scanning at each iso-energy layer is performed along the contour of the target volume and on similar equidistant contours in the interior of the target volume, thereby shaping the dose by using the beam intensity modulation along the contours.

12. The process according to claim 8,

wherein

an imaged collimation on the scanned beam is applied by using a collimator block being at least one of radially and azimuthally moved into the proton beam at the coupling point of the beam transport system (BT).