Precise magnetic field control of the scanning magnets for the APTRON beam delivery system

Miao, Chunhui; Liu, Ming; Yin, Chongxian; Zhao, Zhentang

doi:10.1007/s41365-017-0324-6

Cited by 12 publications

(4 citation statements)

References 9 publications

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“…Random error is a common phenomenon in radiotherapy, even in the testing process [ 5 , 30 ]. Beam point loss and beam line loss are fewer common phenomena in reality, which are the worst-case scenario we assumed.…”

Section: Methodsmentioning

confidence: 99%

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The influence of beam delivery uncertainty on dose uniformity and penumbra for pencil beam scanning in carbon-ion radiotherapy

Gao

Liu

et al. 2021

PLoS ONE

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The dose uniformity and penumbra in the treatment field are important factors in radiotherapy, which affects the outcomes of radiotherapy. In this study, the integrated depth-dose-distributions (IDDDs) of 190 MeV/u and 260 MeV/u carbon beams in the active spot-scanning delivery system were measured and calculated by FLUKA Monte Carlo simulation based on the Heavy Ion Medical Machine (HIMM). Considering the dose distributions caused by secondary particles and scattering, we also used different types of pencil beam (PB) models to fit and compare the spatial distributions of PB. We superposed a bunch of PB to form a 20×20 cm2 treatment field with the double Gaussian and double Gaussian logistic beam models and calculated the influence of beam delivery error on the field flatness and penumbra, respectively. The simulated IDDDs showed good agreement with the measured values. The triple Gaussian and double Gaussian logistic beam models have good fitness to the simulated dose distributions. There are different influences on dose uniformity and penumbra resulting from beam uncertainties. These results would be helpful for understanding carbon ion therapy, and physical therapists are more familiar with beam characteristics for active scanning therapy, which provides a reference for commissioning and optimization of treatment plans in radiotherapy.

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Section: Methodsmentioning

confidence: 99%

“…An important drawback of the passive uniform scanning technique is the passive elements (e.g., range shifter) in the nozzle, which increases the lateral penumbra in the patient [ 4 ]. The active spot scanning technique can theoretically improve the dose conformation [ 5 ].…”

Section: Introductionmentioning

confidence: 99%

The influence of beam delivery uncertainty on dose uniformity and penumbra for pencil beam scanning in carbon-ion radiotherapy

Gao

Liu

et al. 2021

PLoS ONE

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“…There are two scanning magnets, two dose monitors, one position monitor, and their control cabinet in the SAPT irradiation system [22]. The scanning magnets kick the proton beam to the target position, while the magnetic field is measured and controlled [23]. The beam position is monitored by the position ion chamber.…”

Section: Beam Delivery Systemmentioning

confidence: 99%

SAPT: a synchrotron-based proton therapy facility in Shanghai

Zhang,

Li,

Shen

et al. 2023

NUCL SCI TECH

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Because of its excellent dose distribution, proton therapy is becoming increasingly popular in the medical application of cancer treatment. A synchrotron-based proton therapy facility was designed and constructed in Shanghai. The synchrotron, beam delivery system, and other technical systems were commissioned and reached their expected performances. After a clinical trial of 47 patients was finished, the proton therapy facility obtained a registration certificate from the National Medical Products Administration. The characteristics of the accelerator and treatment systems are described in this article.

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“…The beam sequentially irradiates all the spots which are arranged inside and around the target volume, as if painting it out by a pencil. The beam motion is controlled by the magnetic field generated by a pair of electromagnets called scanning magnets (Miao et al, 2017) which are installed in the beam irradiation nozzle. In order to determine the operation pattern of the scanning magnets, both the positions of all the spots and the number of particles given to each spot must be determined by using the optimization technique.…”

Section: Introductionmentioning

confidence: 99%

Layout optimization of the beam spot locations scanned by electromagnets in particle beam therapy

Sakamoto

NAGASHIMA

Sato

et al. 2022

Mechanical Engineering Journal

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This paper presents a layout optimization method of the spot locations of pencil beam scanning for particle beam cancer therapy. With the pencil beam scanning technique, the particle beam is scanned from spot to spot in the tumor by using scanning magnets. To provide clinically ideal dose distributions and less-invasive treatment to the patients, both the spot locations and the number of particles given to each spot should be optimized. However, the spot layout is fixed with a lattice pattern in many prior studies. We propose the optimization method to derive the non-lattice spot layout to realize an acceptable dose distribution with a reduced number of spots. With the proposed method, a large enough number of spots were located densely at the initial state, and then the spots with the smallest contribution were removed one by one through iterations. The number of particles given to each spot was determined by solving a quadratic problem. Furthermore, we also propose the idea to accelerate the optimization process by simultaneously removing multiple spots. The algorithm was confirmed by numerical examples of both two-dimensional and three-dimensional cases. The dose quality with the optimized spot layout was better than that with the conventional lattice spot patterns, with all tested cases. In the optimized spot layout, the spots were located on the closed lines which were concentric to the target contour. We also confirmed the proposed method of multiple-remotion can accelerate the optimization process without violating the dose quality.

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Precise magnetic field control of the scanning magnets for the APTRON beam delivery system

Cited by 12 publications

References 9 publications

The influence of beam delivery uncertainty on dose uniformity and penumbra for pencil beam scanning in carbon-ion radiotherapy

The influence of beam delivery uncertainty on dose uniformity and penumbra for pencil beam scanning in carbon-ion radiotherapy

SAPT: a synchrotron-based proton therapy facility in Shanghai

Layout optimization of the beam spot locations scanned by electromagnets in particle beam therapy

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