Proton accelerator complex for radio-isotopes and therapy

• US 20070108922A1
• Filed: 05/24/2006
• Published: 05/17/2007
• Est. Priority Date: 11/11/2005
• Status: Active Grant

• Current Assignee: Fondazione Per Adroterapia Oncologica- Tera
• Original Assignee: Fondazione Per Adroterapia Oncologica- Tera
• Inventors: Amaldi, Ugo
• Granted Patent: US 7,554,275 B2
• Time in Patent Office: Days
• US Class Current: 315/502
• CPC Class Codes: A61N 2005/1087 Ions; Protons
• CPC Class Codes: H05H 6/00 Targets for producing nuclear reactions supports for targets or objects to be irradiated G21K5/08 ; preparation of tritium C01B4/00; targets, e.g. pellets for fusion reactions by laser or charged particles beam injection H05H1/22

Abstract

A complex of proton accelerators, includes the following functionally interconnected components: a proton source, a cyclotron, at least one target, located either internally or externally to the cyclotron, a medium energy beam transport magnetic channel, a radiofrequency linear accelerator, a high energy beam transport channel towards an area dedicated to the irradiation of tumours with proton beams, as well as a modular system for supplying radio frequency power capable of feeding, independently two or more accelerating modules of the linac. An integrated computerized system controls the complex of accelerators so to carry out, either in alternation or simultaneously, both the production of radioisotopes—for medical, industrial and therapeutical purposes—and the therapeutical irradiation of, even deep seated tumours. The complex of accelerators produces proton beams which, applying the recently developed ‘spot scanning’ technique, are more suited for the tumour irradiation than the ones produced by cyclotrons and synchrotrons.

Claims

1. Accelerator complex of proton beams, particularly for medical use, comprising the following operatively interlinked components:

a) a conventional or super-conducting cyclotron;

b) a proton source, internally or externally located with respect to the cyclotron;

c) at least one target, internally or externally located with respect to the cyclotron, which is used to the production of radioisotopes using the proton beam or a secondary neutron beam;

d) a proton radiofrequency linear accelerator (linac), located after the cyclotron in the acceleration sequence;

e) a Medium Energy Beam Transfer channel (MEBT) connected to one of the output beam lines of the cyclotron on one side and to the input of the radiofrequency linear accelerator on the other side and equipped with one or more mechanical and/or magnetic and/or electrostatic “

choppers” and

“

gates”

used to improve the security, to reduce the irradiation of the components located downstream of MEBT and to vary the intensity of the beams accelerated by the linac for proton therapy;

f) a High Energy Beam Transfer channel (HEBT) connected to the output of the radiofrequency linear accelerator on one side and to one or more systems for the distribution of the proton dose to the patient on the other side;

g) a modular system for supplying radiofrequency power to the linac accelerating modules which powers in a separate and independent way one or more modules, and

h) a fully integrated computer controlled system which controls the full accelerator system and is capable of performing at whish, alternatively or at the same time, the task of radioisotope production for medical or industrial purposes, and/or the task of irradiating tumours, shallow or deep seated.

2. Accelerator complex for protons according to claim 1, characterized by the fact that said proton source is Multicusp, or ECR, or EBIS, or of any other proper kind.

3. Accelerator complex for protons according to claim 1, characterized by the fact that said proton source is connected to the cyclotron through a Low Energy Beam Transport channel LEBT which is used for pulsing and/or varying the intensity of the proton pulses accelerated in the cyclotron and in the linac.

4. Accelerator complex for protons according to claim 1, characterized by the fact that the proton beam entering the radiofrequency linear accelerator is either continuous or is pulsed according to the repetition rate of said linac.

5. Accelerator complex for protons according to claim 1, characterized by the fact that said medium energy beam transfer channel (MEBT) is provided with one or more mechanical, electrical or magnetic “

choppers”

adapted to increase the safety thereof, to reduce the irradiaton of the downstream placed components and to vary the intensity of the prontherapy beams.

6. Accelerator complex for protons according to claim 1, characterized by the fact that said radiofrequency linear accelerator has a resonant frequency larger or equal to 1 GHz.

7. Accelerator complex for protons according to claim 1, characterized by the fact that said radiofrequency linear accelerator has a modular structure and includes a first accelerating section of the DTL type and a successive accelerating section of the CCL type, or only one accelerating section of the DTL type, or only one accelerating section of the CCL type, wherein the radiofrequency power is distributed in a adjustable and independent way either to each accelerating module or to a group of them.

8. Accelerator complex for protons according to claim 1, characterized by the fact that in the radiofrequency linear accelerator the accelerating structures of the DTL or CCL type are composed by a variable number of modules, also not all aligned on the same geometrical straight line.

9. Accelerator complex for protons according to claim 1, characterized by the fact that the accelerating modules are fed by radiofrequency power production systems which are separated and modular in order to facilitate their substitution and repair in case of failure.

10. Accelerator complex for protons according to claim 1, characterized by the fact that said radiofrequency power supply system is composed by modules capable of controlling the amplitude and the phase of the radiofrequency signal sent to the accelerating modules and thus adjust the energy of the beam sent to the proton therapy rooms.

11. Accelerator complex for protons according to claim 1, characterized by the fact that said cyclotron, conventional or super-conducting, pre-accelerates the proton beam up to a maximum energy which is in the range from about 10 to about 100 MeV.

12. Accelerator complex for protons according to claim 1, characterized by the fact that said two accelerating sections DTL and CCL of the radiofrequency linac, if both present, work at the same frequency, for example at about 3 GHz or about 5.7 GHz, or at multiple frequencies, for example at about 1.5 and about 3 GHz, respectively.

13. Accelerator complex for protons according to claim 2, characterized by the fact that to accelerate protons from 30 MeV only the CCL structure is used for the linac with the frequency 2.998 GHz and with substantially the following parameters:

Type of linac SCL Frequency [MHz] 2998 Input energy [MeV] 30 Output energy [MeV] 210 Number of accelerating cells per accelerating 14 structure Number of accelerating structures per module 2 Number of modules (equivalent to number of 20 klystrons) Total length of the linac [m] 16.4 Repetition rate of the pulses [Hz] 200 Pulse length[μ

s] 2-5 Average power per module (pulses;

2 μ

s-5 μ

s) 1.5-3.0 [kW] Power required by the linac [kW] 30-61 Duty cycle [%] 0.04-0.1 

Magnetic gradient of the quadrupoles [T/m] 170-130 Normalized transversal acceptance [π

mm mrad] 3.4

14. Accelerator complex for protons according to claim 2, characterized by the fact that to accelerate protons from 15 MeV the two accelerating structures are used for the radiofrequency linac, for the DTL type at a frequency of 1.499 GHz and for the CCL type at a frequency 2.998 GHz and with substantially the following parameters:

Type of linac DTL SCL Frequency [MHz] 1499 2998 Input energy [MeV] 15 67 Output energy [MeV] 67 210 Number of accelerating cells per 7 14 accelerating structure Number of accelerating structures 8-6-4—

4 2 per module Number of modules (equivalent to 4 14 number of klystrons) Total length of the linac [m] 6.2 12.6 Repetition rate of the pulses 200 200 [Hz] Pulse length[μ

s] 2-5 2-5 Average power per module (pulses;

1.5-3 

 

1.5-3 

 

2 μ

s-5 μ

s) [kW] Power required by the linac [kW]  

6-12 21-42 Duty cycle [%] 0.04-0.1 

0.04-0.1 

Magnetic gradient of the 156-144 170-130 quadrupole [T/m] (FODO configuration) Normalized transversal acceptance 3.3 4.0 [π

mm mrad]

15. Accelerator complex for protons according to claim 2, characterized by the fact that to accelerate protons from 72 only the CCL structure is used for the radiofrequency linac with the frequency 2.998 GHz and with substantially the following parameters:

Type of linac SCL Frequency [MHz] 2998 Input energy [MeV] 72 Output energy [MeV] 240 Number of accelerating cells per accelerating 16 structure Number of accelerating structures per module 2 Number of modules (equivalent to number of 14 klystrons) Total length of the linac [m] 14.6 Repetition rate of the pulses [Hz] 200 Pulse length[μ

s] 2-5 Average power per module (pulses;

2 μ

s-5 μ

s) 1.7-3.3 [kW] Power required by the linac [kW] 23-46 Duty cycle [%] 0.04-0.1 

Magnetic gradient of the quadrupole [T/m] 166-128 (FODO configuration) Normalized transversal acceptance [π

mm mrad] 3.9

16. Accelerator complex for protons according to claim 1, characterized by the fact that the integrated computer control system used for the cyclotron and for the modules of the radiofrequency linac, for the distribution and the energy of the different proton beams for the production of radioisotopes and for protontherapy, is composed of a distributed system of computers formed by a first group of computers dedicated to the operators and to the foreseen procedures and a second group of computers dedicated to the high technology apparata and a specific software that allows the operation of the different proton beams either in parallel or one at the time.

17. Method of proton beams acceleration for alternate or simultaneous use in diagnostics and protontherapy by using an accelerator complex for protons according to claim 1 comprising:

producing a proton beam with a suitable proton/ion source;

injecting the beam in a cyclotron;

extracting the continuous proton beam in two or more beam lines;

feeding at least two beam lines in alternation or simultaneously with a proton beam for isotope production;

feeding at least one beam line in alternation or simultaneously with a proton beam for protontherapy;

gating and chopping if needed the beam in the protontherapy beam line and inject it in a compact linac proton accelerator;

accelerate the beam in the linac such as to obtain at the linac output a protontherapy beam of the desired variable output energy and intensity, and with a pulsed time structure, able to perform active spot scanning as well as passive scanning at the patient;

distribute the protontherapy beam in one or more than one room were the therapeutic dose can be delivered to the patient in a suitable controlled way.

18. Use of an accelerator complex for protons according to claim 1, in the field of medical and/or industrial applications and/or in research in physics or for the production of neutrons used for the production of radioisotopes and/or for BNCT and/or for BNCS.