An improved beam splitting method for intensity modulated proton therapy

Yang, Jinhe; He, Peng; Wang, Hui; Sun, Guangdong; Zheng, Hairong; Jia, Jing

doi:10.1088/1361-6560/ab9b55

Cited by 4 publications

(4 citation statements)

References 26 publications

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“…Based on ray casting, our approach inherits the intrinsic challenges when dealing with material interfaces that can affect dose calculation accuracy. One technique to address these issues is the beam splitting technique used in many pencil beam algorithms (Schaffner et al 1999, Soukup et al 2005, Padilla-Cabal et al 2018, 2020a, Yang et al 2020, which, however, results in increased calculation times. These pencil beam decomposition algorithms are better suited to deal with superficial density heterogeneities, while the ray casting algorithm usually performs better for inhomogeneities closer to the Bragg peak, as discussed by Schaffner et al (1999).…”

Section: Discussionmentioning

confidence: 99%

A fast analytical dose calculation approach for MRI-guided proton therapy

Duetschler,

Winterhalter,

Meier

et al. 2023

Phys. Med. Biol.

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Objective. Magnetic resonance (MR) is an innovative technology for online image guidance in conventional radiotherapy and is also starting to be considered for proton therapy as well. For MR-guided therapy, particularly for online plan adaptations, fast dose calculation is essential. Monte Carlo (MC) simulations, however, which are considered the gold standard for proton dose calculations, are very time-consuming. To address the need for an efficient dose calculation approach for MRI-guided proton therapy, we have developed a fast GPU-based modification of an analytical dose calculation algorithm incorporating beam deflections caused by magnetic fields. Approach. Proton beams (70–229 MeV) in orthogonal magnetic fields (0.5/1.5 T) were simulated using TOPAS-MC and central beam trajectories were extracted to generate look-up tables (LUTs) of incremental rotation angles as a function of water-equivalent depth. Beam trajectories are then reconstructed using these LUTs for the modified ray casting dose calculation. The algorithm was validated against MC in water, different materials and for four example patient cases, whereby it has also been fully incorporated into a treatment plan optimisation regime. Main results. Excellent agreement between analytical and MC dose distributions could be observed with sub-millimetre range deviations and differences in lateral shifts <2 mm even for high densities (1000 HU). 2%/2 mm gamma pass rates were comparable to the 0 T scenario and above 94.5% apart for the lung case. Further, comparable treatment plan quality could be achieved regardless of magnetic field strength. Significance. A new method for accurate and fast proton dose calculation in magnetic fields has been developed and successfully implemented for treatment plan optimisation.

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Section: Discussionmentioning

confidence: 99%

A fast analytical dose calculation approach for MRI-guided proton therapy

Duetschler,

Winterhalter,

Meier

et al. 2023

Phys. Med. Biol.

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“…For the purpose of lateral beam splitting the original spot's central axis is placed at the origin of a 2D lateral grid. Given the radial symmetry of the Gaussian, placing sub-spots or beamlets on N r + 1 concentric rings with radii r i around the original spot location was chosen, in a similar manner to Yang's method (Yang et al 2020). On a given ring i the beamlets share the same weight w i and spread σ i .…”

Section: Optimized Gaussian Beam Splittingmentioning

confidence: 99%

“…Prior to the optimization the number of rings N r , the number of points on each ring n i and the ring offsets α i are specified. As opposed to Yang's (2020) approach this formalism and implementation is not restricted to a number of pre-defined schemes. In principle any number of beamlets per ring and number of rings can be optimized.…”

Section: Optimized Gaussian Beam Splittingmentioning

confidence: 99%

Yet anOther Dose Algorithm (YODA) for independent computations of dose and dose changes due to anatomical changes

Burlacu,

Lathouwers,

Perkó

2024

Phys. Med. Biol.

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Objective: To assess the viability of a physics-based, deterministic and adjoint-capable algorithm for performing treatment planning system independent dose calculations and for computing dosimetric differences caused by anatomical changes.Approach: A semi-numerical approach is employed to solve two partial differential equations for the proton phase-space density which determines the deposited dose. Lateral hetereogeneities are accounted for by an optimized (Gaussian) beam splitting scheme. Adjoint theory is applied to approximate the change in the deposited dose caused by a new underlying patient anatomy.Main results: The quality of the dose engine was benchmarked through three-dimensional gamma index comparisons against Monte Carlo simulations done in TOPAS. The worst passing rate for the gamma index with (1 mm, 1 %, 10 % dose cut-off) criteria is 94.55 %. The effect of delivering treatment plans on repeat CTs was also tested. For a non-robustly optimized plan the adjoint component was accurate to 5.7 % while for a robustly optimized plan it was accurate to 4.8 %.Significance: YODA is capable of accurate dose computations in both single and multi spot irradiations when compared to TOPAS. Moreover, it is able to compute dosimetric differences due to anatomical changes with small to moderate errors thereby facilitating its use for patient-specific quality assurance in online adaptive proton therapy.

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“…The top three subspecialties are radiation imaging (218 papers), radiation therapy (70 papers), and magnetic resonance (42 papers). Within the subspecialty of radiation therapy, the number of publications are 15 papers in the field of clinical implementation [41][42][43][44][45][46][47][48][49][50][51][52][53][54][55], 11 papers in the field of plan optimization [56][57][58][59][60][61][62][63][64][65][66], 14 papers in the field of plan evaluation [67][68][69][70][71][72][73][74][75][76][77][78][79][80], and 12 papers in the field of quality assurance [81][82][83][84][85][86][87][88]…”

Section: Scientific Researchmentioning

confidence: 99%

The status of medical physics in radiotherapy in China

Yan

Huang

et al. 2021

Physica Medica

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To present an overview of the status of medical physics in radiotherapy in China, including facilities and devices, occupation, education, research, etc. Materials and methods: The information about medical physics in clinics was obtained from the 9-th nationwide survey conducted by the China Society for Radiation Oncology in 2019. The data of medical physics in education and research was collected from the publications of the official and professional organizations. Results: By 2019, there were 1463 hospitals or institutes registered to practice radiotherapy and the number of accelerators per million population was 1.5. There were 4172 medical physicists working in clinics of radiation oncology. The ratio between the numbers of radiation oncologists and medical physicists is 3.51. Approximately, 95% of medical physicists have an undergraduate or graduate degrees in nuclear physics and biomedical engineering. 86% of medical physicists have certificates issued by the Chinese Society of Medical Physics. There has been a fast growth of publications by authors from mainland of China in the top international medical physics and radiotherapy journals since 2018. Conclusions: Demand for medical physicists in radiotherapy increased quickly in the past decade. The distribution of radiotherapy facilities in China became more balanced. High quality continuing education and training programs for medical physicists are deficient in most areas. The role of medical physicists in the clinic has not been clearly defined and their contributions have not been fully recognized by the community.Prof. Xu Haichao in 1940s at Peking Union Medical College (PUMC). He worked with Prof. Marvin Williomus, an American medical physicist, to treat cancer patients using a 400 kV X-ray unit [7]. The department of radiology in Caner Institute of Chinese Academy of Medical Sciences (CICAMS) started to treat patients with a Cobalt-60 unit in 1958. At the same year, the division of radiation physics in CICAMS was founded. They made the manual multi-leaf collimator and installed it on Cobalt-60 machine in 1965. Later, they made the remote control system for brachytherapy machine using Cobalt-60 source ball in 1965Cobalt-60 source ball in -1967.From 1970, China began to build linear accelerators and on-board imaging devices. As a result, 25 MeV Betatron, Simulator and Cobalt-60 brachytherapy machine were produced by Tianjing therapeutic instrument factory [9]. Meanwhile, Beijing Medical Apparatus and Instruments Institute built the first linear accelerator [10]. Since 1976, the major hospitals started to purchase high-end linear accelerators, CT, Brachytron and planning software from USA and Europe [11]. Following the clinical application of the linear accelerators, text books in Chinese

show abstract

An improved beam splitting method for intensity modulated proton therapy

Cited by 4 publications

References 26 publications

A fast analytical dose calculation approach for MRI-guided proton therapy

A fast analytical dose calculation approach for MRI-guided proton therapy

Yet anOther Dose Algorithm (YODA) for independent computations of dose and dose changes due to anatomical changes

The status of medical physics in radiotherapy in China

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