Device And Method For Particle Beam Production

• US 20120160996A1
• Filed: 06/24/2010
• Published: 06/28/2012
• Est. Priority Date: 06/24/2009
• Status: Active Grant

• Current Assignee: Ion Beam Applications s.a.
• Original Assignee: Ion Beam Applications s.a.
• Inventors: Jongen, Yves
• Granted Patent: US 9,451,688 B2
• Time in Patent Office: Days
• US Class Current: 250/252.1
• CPC Class Codes: A61N 2005/1087 Ions; Protons
• CPC Class Codes: A61N 5/1048 Monitoring, verifying, controlling systems and methods
• CPC Class Codes: A61N 5/1067 in real time, i.e. during treatment
• CPC Class Codes: H05H 7/00 Details of devices of the types covered by groups H05H9/00, H05H11/00, H05H13/00

Abstract

The present invention relates to a pulsed beam particle accelerator which can be used for particle radiation therapy. More particular, a device and method are provided to control the number of particles within a beam pulse. The particle accelerator comprises means for varying the number of particles within each beam pulse of said pulsed ion beam from a minimum value to a maximum value as function of the value of a beam control parameter. For each particle irradiation the required number of particles for each beam pulse is controlled by defining a value for said beam control parameter based on calibration data.

Claims

1. A particle accelerator of the type synchrocyclotron, linear accelerator or fixed field alternating gradient accelerator, for producing an energetic pulsed ion beam, said accelerator comprising an ion source for producing ions and a radio frequency acceleration system for accelerating said ions, said accelerator comprising:

Means for varying the number of particles within each beam pulse of said pulsed ion beam from a minimum value to a maximum value as function of the value of a beam control parameter, said parameter being related to the operation of the ion source and/or of the RF system,

A beam control device comprising;

an interface for receiving an external instruction specifying the required number of particles for each beam pulse;

a calibration table or parameter values of a mathematical function defining the relation between the value of said beam control parameter and said number of particles within a beam pulse, said table or parameters being stored on a suitable storing means;

means for determining the required value of said beam control parameter corresponding to said required number of particles using said calibration table or said mathematical function;

an interface for sending said required value of said beam control parameter to said means for varying the number of particles.

2. The particle accelerator according to claim 1 wherein said beam control device further comprises:

an interface for receiving an external signal specifying the measured number of particles within a beam pulse, said measurement being performed with a beam monitor;

means for updating said calibration table or said parameter values in dependence of said measured number of particles.

3. The particle accelerator according to claim 2 further comprising:

control means for automatically generating said calibration table or said mathematical function by defining a number of different values for said beam control parameter, producing for each said value a beam pulse and measuring the corresponding number of particles within each produced beam pulse.

4. The particle accelerator according to claim 2 further comprising:

control means for automatically readjusting said calibration table or said mathematical function after each beam pulse produced by said accelerator, said readjusting being made by comparing the said measured number of particles with the said required number of particles.

5. The particle accelerator according to claim 1, wherein said means for varying the number of particles within each beam pulse comprises means for varying the arc current of said ion source.

6. The particle accelerator according to claim 1, wherein said means for varying the number of particles within each beam pulse comprises means for varying the acceleration voltage of said radio frequency acceleration system.

7. The particle accelerator according to claim 1, wherein said means for varying the number of particles within each beam pulse comprises means for varying the time period during which the said ion source is turned on.

8. The particle accelerator according to claim 1, wherein said means for varying the number of particles within each beam pulse comprises means for varying the time difference between the moment the ion source is turned on and the moment the ions can start acceleration using said radio frequency acceleration system.

9. A particle radiotherapy system comprising a particle accelerator according to claim 1.

10. The particle radiotherapy system according to claim 9 further comprising:

A spot scanning beam delivery device configured to provide a series of spot irradiations.

11. The particle radiotherapy system according to claim 10 whereby said spot scanning beam delivery device is configured to use a single beam pulse for each said spot irradiation.

12. The particle radiotherapy system according to claim 10 wherein said spot scanning beam delivery device is configured to use two beam pulses to deliver the total required number of particles for each said spot irradiation, said particle radiotherapy device is further comprising:

Means to define the required number of particles for the first of said two beam pulses as being a given percentage of the total required number of particles to be delivered for said spot irradiation;

Means to specify the required number of particles of the second of said two beam pulses as being the said total required number of particles for said spot irradiation minus the measured number of particles already delivered with said first beam pulse.

13. The particle radiotherapy system according to claim 10 wherein said spot scanning beam delivery device is configured to use a variable number of beam pulses for each said spot irradiation, said particle radiotherapy device further comprising:

Means to define the required number of particles for all beam pulses of said variable number of beam pulses such that the sum of the required number of particles of all beam pulses except the last beam pulse equals a given percentage of the total number of particles to be delivered for said spot irradiation.

Means to specify the required number of particles for the last beam pulse of said variable number of beam pulses as being the total number of particles to be delivered for the said spot irradiation minus the measured number of particles already delivered for said spot irradiation.

16. A method for performing a series of spot irradiations by a number of beam pulses with the system of claim 10, wherein the method comprises for each spot of said series of spot irradiations the steps of:

defining the total required number of particles T1 to be delivered to said spot,

specifying a total number of beam pulses for delivering said number of particles T1 and defining a required number of particles for each beam pulse of said total number of beam pulses,

applying said beam pulses, except the last beam pulse,

measuring the number of particles Al of said beam pulses except the last beam pulse,

before applying the last beam pulse, calculating the difference T1−

A1 between the total required number of particles and the measured number of particles,

specifying the required amount of particles in the last beam pulse A2 as equal to said difference T1−

A1,

applying the last beam pulse.

14. A method for controlling the number of particles within a beam pulse from a pulsed beam particle beam accelerator, of the type synchrocyclotron, linear accelerator or fixed field alternating gradient accelerator, said beam pulses being usable for performing particle beam irradiations, said accelerator comprising means to vary the number of particles within each beam pulse as a function of the value of a beam control parameter, said beam control parameter being related to the operation of the ion source and/or the RF system, said method comprising the steps of:

Generating calibration data comprising the sub-steps of;

1. Applying a value of said beam control parameter to said means for varying number of particles;

2. Producing and extracting a beam pulse from said accelerator;

3. Measuring number of particles within said extracted beam pulse;

4. Storing said measured number of particles within said extracted beam pulse; and

5. Repeating steps 1 to 4 for a series of beam control parameter values;

Performing particle beam production comprising the sub-steps of;

1. Receiving an external instruction specifying for each beam pulse the required number of particles within a beam pulse;

2. Determining the required value of said beam control parameter corresponding to said required number of particles using said calibration data;

3. Applying said required value of beam control parameter to said means for varying number of particles;

4. Producing and extracting beam pulse from said accelerator.

15. The method according to claim 14 wherein said step of performing particle beam production further comprises the sub-steps of:

5. Measuring the number of particles within said extracted beam pulse;

6. Making a comparison between said measured number of particles with said required number of particles;

7. Applying a correction to said calibration data based on said comparison.