An achromatic gantry for proton therapy with fixed-field superconducting magnets

Brouwer, Lucas; Huggins, Anthony; Wan, Weishi

doi:10.1142/s0217751x19420235

Cited by 14 publications

(23 citation statements)

References 16 publications

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“…The results of Ref. [6] motivate a quantitative cost analysis of the superconducting magnet system for the fixed-field gantry in Brouwer et al (2019) [5]. To balance competing objectives of conductor and cryogenics costs, a thermoeconomic model is required to convert capital and operating costs into a Net Present Value (NPV [$]) or cost rate ([$/hr]).…”

Section: Pat I Entmentioning

confidence: 87%

“…In this work, we develop a thermoeconomic model of a multi-stage, conduction cooled magnet system and apply it to optimize conductor and cryogenics choices for the novel gantry layout in Ref. [5]. The lifetime gantry ownership costs are optimized with Nb-Ti, Nb 3 Sn, REBCO and Bi-2223, and an emphasis is given to conductors that scale to higher fields.…”

Section: Pat I Entmentioning

confidence: 99%

“…Brouwer et al (2019) [5] developed a new magnet and optics solution with full momentum acceptance; 70-220 MeV proton beams are transmitted with the superconducting magnet system at fixed field. As illustrated in Fig.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Thermoeconomic cost optimization of superconducting magnets for proton therapy gantries

Teyber¹,

Brouwer²,

Godeke³

et al. 2020

Supercond. Sci. Technol.

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A compact gantry delivering 70-220 MeV protons with fixed field in the superconducting magnets could reduce the cost and improve the adoption of proton therapy. While a number of magnet and cryogenics designs have been proposed, the combined capital and operating costs of state-of-the-art superconducting materials have not been analyzed. In response, we develop a thermoeconomic model of a multi-stage, conduction cooled gantry lattice and analyze the cryocooler operating cost, cryocooler capital cost and conductor capital cost for Nb-Ti, Nb 3 Sn, REBCO and Bi-2223 over a continuous range of magnet temperatures, and a differential evolution algorithm is used to identify the optimal combination of thermal intercept temperatures. Although Nb 3 Sn yields the lowest Net Present Value (NPV) of $111.7k at a magnet temperature of 9.4 K, the optimized Bi-2223 design at 12.8 K approaches the realm of commercial feasibility by offering improved thermal stability and forgoing the need for costly conductor heat treatment and magnet quench training. Furthermore, it was found that Nb 3 Sn was more cost effective than Nb-Ti and that REBCO was not economically viable for the parameters of this investigation. The thermoeconomic model developed herein can optimize conductor choices, magnet temperatures and thermal staging which has value for any conduction-cooled superconducting magnet.

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Section: Pat I Entmentioning

confidence: 87%

Section: Pat I Entmentioning

confidence: 99%

See 1 more Smart Citation

Thermoeconomic cost optimization of superconducting magnets for proton therapy gantries

Teyber¹,

Brouwer²,

Godeke³

et al. 2020

Supercond. Sci. Technol.

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“…Brouwer et al [15] developed a new SC magnet and beam dynamics solution capable of transporting 70-225 MeV protons with fixed-field for proton therapy gantries (Fig. 1).…”

Section: A Magnet Layoutmentioning

confidence: 99%

“…The next case study is the magnetic field profile of Brouwer et al [15] for a large momentum acceptance proton therapy gantry. Although the original magnet design consists of an iron-core Nb-Ti magnet, we apply the inverse Biot-Savart topology optimization to demonstrate the recreation of optics optimized magnetic field distributions.…”

Section: B Proton Therapy Gantrymentioning

confidence: 99%

Inverse Biot–Savart Optimization for Superconducting Accelerator Magnets

et al. 2021

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Superconducting (SC) magnets for accelerator concepts are often synthesized by numerically optimizing magnetic field waveforms, a process that requires a subsequent solution of a constrained inverse problem to identify suitable SC magnet windings. When the desired field distribution is intuitive, the inverse process is facilitated by seeding preconceived coil distributions into design optimization methods for refinement. With more complex magnetic field distributions, an initial design may be unknown, and topology optimization tools are required to synthesize current distributions without apriori guidance from a subject matter expert. In this work, we develop a constrained inverse Biot-Savart topology optimization methodology that synthesizes optimal distributions of current density in racetrack-like SC coils. The problem structure is exploited through a computationally efficient quadratic programming formulation, and the method is applied to recently published magnetic field waveforms for a recirculating proton phase shifter, a proton therapy gantry, and dipole magnets with sharp field transitions. The method and results herein identify novel winding configurations that can help magnet designers bring accelerator concepts to fruition.

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Beam properties within the momentum acceptance of a clinical gantry beamline for proton therapy

et al. 2022

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Purpose Energy changes in pencil beam scanning proton therapy can be a limiting factor in delivery time, hence, limiting patient throughput and the effectiveness of motion mitigation techniques requiring fast irradiation. In this study, we investigate the feasibility of performing fast and continuous energy modulation within the momentum acceptance of a clinical beamline for proton therapy. Methods The alternative use of a local beam degrader at the gantry coupling point has been compared with a more common upstream regulation. Focusing on clinically relevant parameters, a complete beam properties characterization has been carried out. In particular, the acquired empirical data allowed to model and parametrize the errors in range and beam current to deliver clinical treatment plans. Results For both options, the local and upstream degrader, depth‐dose curves measured in water for off‐momentum beams were only marginally distorted (γ(1%, 1 mm) > 90%) and the errors in the spot position were within the clinical tolerance, even though increasing at the boundaries of the investigated scan range. The impact on the beam size was limited for the upstream degrader, while dedicated strategies could be required to tackle the beam broadening through the local degrader. Range correction models were investigated for the upstream regulation. The impaired beam transport required a dedicated strategy for fine range control and compensation of beam intensity losses. Our current parameterization based on empirical data allowed energy modulation within acceptance with range errors (median 0.05 mm) and transmission (median –14%) compatible with clinical operation and remarkably low average 27 ms dead time for small energy changes. The technique, tested for the delivery of a skull glioma treatment, resulted in high gamma pass rates at 1%, 1 mm compared to conventional deliveries in experimental measurements with about 45% reduction of the energy switching time when regulation could be performed within acceptance. Conclusions Fast energy modulation within beamline acceptance has potential for clinical applications and, when realized with an upstream degrader, does not require modification in the beamline hardware, therefore, being potentially applicable in any running facility. Centers with slow energy switching time can particularly profit from such a technique for reducing dead time during treatment delivery.

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An achromatic gantry for proton therapy with fixed-field superconducting magnets

Cited by 14 publications

References 16 publications

Thermoeconomic cost optimization of superconducting magnets for proton therapy gantries

Thermoeconomic cost optimization of superconducting magnets for proton therapy gantries

Inverse Biot–Savart Optimization for Superconducting Accelerator Magnets

Beam properties within the momentum acceptance of a clinical gantry beamline for proton therapy

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