# US 10,864,384 B2 · Non-achromatic compact gantry

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- Number: US 10,864,384 B2
- Document ID: US10864384B2
- Status: Granted
- Kind: B2
- Application number: 16/369,995
- Filed: 2019-03-29
- Published: 2020-10-01
- Granted: 2020-12-15
- Earliest claimed: 2019-03-29
- Assignees: Varian Medical Systems Particle Therapy GmbH
- Applicants: Varian Medical Systems Particle Therapy GmbH
- Inventors: Anthony Michael Huggins; Michael Schillo
- Web page: https://patentgrep.com/patent/US10864384B2

## CPC

- A61N 5/1081: {Rotating beam systems with a specific mechanical construction, e.g. gantries}
- G21K 1/093: by magnetic means
- G21K 5/04: with beam-forming means
- H05H 7/001: {Arrangements for beam delivery or irradiation (irradiation systems per se G21K5/00)}
- A61N 2005/1087: {Ions; Protons}
- A61N 2005/1095: {Elements inserted into the radiation path within the system, e.g. filters or wedges}
- H05H 2007/002: {for modifying beam trajectory, e.g. gantries}
- A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B)
- G21K: HANDLING OF PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
- H05H: PLASMA TECHNIQUE (apparatus or processes specially adapted for producing X-rays H05G2/00); PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS

## Abstract

Embodiments of the present invention provide a compact gantry designed to provide particle therapy using a particle beam. A gantry for providing the particle therapy comprises a first dipole magnet operable to bend a particle beam received from a cyclotron by a first degree amount. The gantry further comprises a plurality of quadrupole magnets configured to condition the beam asymmetrically to produce an asymmetric beam, wherein a configuration of the quadrupole magnets is determined using a dispersion function of a second dipole magnet. Further, the second dipole magnet is operable to receive the asymmetric beam and bend the asymmetric beam by a second degree amount, and wherein the second dipole magnet disperses the asymmetric beam to produce a symmetric beam shape at a treatment iscoenter or at any other reference point.

## Claims

### Claim 1

A gantry for a radiation therapy system, the gantry comprising:
at least one first dipole magnet operable to bend a beam received from a cyclotron by a first degree amount;
a second dipole magnet disposed at the last bend of a beamline; and
a plurality of quadrupole magnets disposed in-line between the at least one first dipole magnet and the second dipole magnet, and configured to condition the beam to produce an asymmetric beam having an amount of asymmetry based on a dispersion function of the second dipole magnet;
wherein the second dipole magnet is operable to receive the asymmetric beam and bend the asymmetric beam by a second degree amount, and wherein the second dipole magnet disperses the asymmetric beam according to the dispersion function to account for the amount of asymmetry and produce a round beam cross-section at a treatment isocenter.

### Claim 2 (depends on 1)

The gantry of claim 1, wherein the beam is a proton beam.

### Claim 3 (depends on 2)

The gantry of claim 2, wherein the proton beam comprises an energy spread.

### Claim 4 (depends on 1)

The gantry of claim 1 wherein the first degree amount is approximately 60 degrees and wherein the second degree amount is approximately 150 degrees.

### Claim 5 (depends on 1)

The gantry of claim 1, wherein the gantry has a height of approximately 1.6 m.

### Claim 6 (depends on 1)

The gantry of claim 1, wherein the second dipole magnet is a superconducting bending magnet.

### Claim 7 (depends on 1)

The gantry of claim 1, further comprising:
a degrader operable to reduce an energy of the proton beam received from the cyclotron.

### Claim 8 (depends on 7)

The gantry of claim 7, wherein the degrader is positioned in-line between the at least one first dipole magnet and the plurality of quadrupole magnets.

### Claim 9 (depends on 7)

The gantry of claim 7, wherein the degrader is disposed subsequent to the second dipole magnet and prior to the treatment isocenter.

### Claim 10 (depends on 1)

The gantry of claim 1, wherein the at least one first dipole magnet and the second dipole magnet comprise high-field dipole magnets.

### Claim 11

A method for performing radiation therapy, the method comprising:
receiving a particle beam emitted from a cyclotron;
bending the beam by a first degree amount using a first dipole magnet;
conditioning the beam asymmetrically to produce an asymmetric beam, wherein the conditioning comprises introducing an amount of asymmetry into the particle beam that based on a dispersion function of a second dipole magnet disposed at the last bend of a beamline; and
bending the asymmetric beam by a second degree amount using the second dipole magnet, wherein the second dipole magnet disperses the asymmetric beam according to the dispersion function to account for the amount of asymmetry and produce a round beam cross-section at a treatment iscoenter.

### Claim 12 (depends on 11)

The method of claim 11, wherein the conditioning is performed using one or more quadrupole magnets disposed in-line between the first dipole magnet and the second dipole magnet.

### Claim 13 (depends on 11)

The method of claim 11, wherein the conditioning is performed using a plurality of multipole magnets disposed in-line between the first dipole magnet and the second dipole magnet.

### Claim 14 (depends on 11)

The method of claim 11, wherein the conditioning is performed using one or more octopole magnets disposed in-line between the first dipole magnet and the second dipole magnet.

### Claim 15 (depends on 11)

The method of claim 11, wherein the conditioning is performed using one or more collimators disposed in-line between the first dipole magnet and the second dipole magnet.

### Claim 16 (depends on 11)

The method of claim 11, further comprising:
prior to the conditioning, reducing an energy of the particle beam using a degrader, wherein the degrader is positioned in-line between the first dipole magnet and the second dipole magnet.

### Claim 17

A compact radiation therapy system, comprising:
a cyclotron operable to emit a beam that is compact;
a gantry coupled to the cyclotron and comprising:
a first dipole magnet operable to bend the beam received from the cyclotron by a first degree amount;
a second dipole magnet disposed at the last bend of a beamline;
a degrader configured to reduce an energy of the beam; and
one or more quadrupole magnets disposed in the beamline between the at least one first dipole magnet and the second dipole magnet, and configured to condition the beam to produce an asymmetric beam having an amount of asymmetry based on a dispersion function of the second dipole magnet;
wherein the second dipole magnet is operable to receive the asymmetric beam and bend the asymmetric beam by a second degree amount, and wherein the second dipole magnet disperses the asymmetric beam according to the dispersion function to account for the amount of asymmetry and produce a round beam cross-section at a point of interest.

### Claim 18 (depends on 17)

The compact radiation therapy system of claim 17, wherein the second dipole magnet is a superconducting bending magnet and wherein further the beam comprises a proton beam.

### Claim 19 (depends on 17)

The compact radiation therapy system of claim 17, wherein the degrader is positioned in-line between the first dipole magnet and the one or more quadrupole magnets.

### Claim 20 (depends on 17)

The compact radiation therapy system of claim 17, wherein the first dipole magnet and the second dipole magnet comprise high-field dipole magnets.

### Claim 21 (depends on 17)

The compact radiation therapy system of claim 17, wherein the beam is a proton beam of a fixed output energy.

### Claim 22 (depends on 17)

The compact radiation therapy system of claim 17, wherein the one or more quadrupole magnets are positioned in-line between the degrader and the second dipole magnet.

### Claim 23 (depends on 17)

The compact radiation therapy system of claim 17, wherein the degrader is disposed between the second dipole magnet and the point of interest.

### Claim 24 (depends on 23)

The compact radiation therapy system of claim 23, wherein the degrader comprises a collimation system.

### Claim 25 (depends on 24)

The compact radiation therapy system of claim 24, wherein the collimation system is dynamic, and wherein a position of the collimation system is adjustable during treatment.

### Claim 26 (depends on 23)

The compact radiation therapy system of claim 23, wherein the point of interest is at a location of the degrader.

### Claim 27 (depends on 23)

The compact radiation therapy system of claim 23, wherein the point of interest is located at a treatment isocenter.

### Claim 28 (depends on 17)

The compact radiation therapy system of claim 17, further comprising a quadrupole magnet positioned before the first dipole magnet.

### Claim 29 (depends on 17)

The compact radiation therapy system of claim 17, further comprising a scanning magnet and wherein the scanning magnet is positioned between the second dipole magnet and the degrader.