Results 141 to 150 of about 4,599 (171)

Effects of spot parameters in pencil beam scanning treatment planning

Medical Physics, 2017
BackgroundSpot size σ (in air at isocenter), interspot spacing d, and spot charge q influence dose delivery efficiency and plan quality in Intensity Modulated Proton Therapy (IMPT) treatment planning. The choice and range of parameters varies among different manufacturers.
Aafke Christine, Kraan, Nicolas, Depauw, Ben, Clasie, Marina, Giunta, Tom, Madden, Hanne M, Kooy   +5 more
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Development of Pencil Beam Scanning Nozzle System

2009
Purpose: Several types of pencil beam scanning system for proton therapy have been developed and applied to clinical treatment. In case of pencil beam scanning using cyclotron as the proton source, it is common to use continuous scanning method. Then scanning speed and beam current are modulated simultaneously[for full text, please go to the a.m. URL]
Asaba, T, Tachikawa, T, Ochi, T, Yamada, M, Nishio, T, Ogino, T   +5 more
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Experimentally validated pencil beam scanning source model in TOPAS

Physics in Medicine and Biology, 2014
The presence of a low-dose envelope, or 'halo', in the fluence profile of a proton spot can increase the output of a pencil beam scanning field by over 10%. This study evaluated whether the Monte Carlo simulation code, TOPAS 1.0-beta 8, based on Geant4.9.6 with its default physics list, can predict the spot halo at depth in phantom by incorporating a ...
Liyong, Lin, Minglei, Kang, Timothy D, Solberg, Christopher G, Ainsley, James E, McDonough   +4 more
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Investigation of scan path optimization in improving proton pencil beam scanning continuous delivery

Physics in Medicine & Biology, 2023
Abstract Objective . To investigate the impact of scan path optimization on the dose accuracy and beam delivery time (BDT) of proton pencil beam scanning in the dose-driven continuous scanning (DDCS). Approach .
Chunbo Liu, Chris J Beltran, Jiajian Shen, Bo Lu, Chunjoo Park, Sridhar Yaddanapudi, Jun Tan, Keith M Furutani, Xiaoying Liang   +8 more
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Parametric Synthesis of Well-Scanning Isophoric Pencil Beams

IEEE Transactions on Antennas and Propagation, 2017
Interest in uniformly illuminated (isophoric) density-tapered planar antenna arrays has recently revived. For arrays consisting of concentric rings of elements, we present a nonstochastic algorithm that calculates ring radii for generation of pencil beams without the need for prior specification of the number of rings.
Salas-Sanchez, AA, Fondevila-Gomez, J, Rodriguez-Gonzalez, JA, Ares-Pena, FJ   +3 more
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Contour scanning, multi-leaf collimation and the combination thereof for proton pencil beam scanning

Physics in Medicine & Biology, 2018
Abstract In proton therapy, the lateral fall-off is often used to spare critical organs. It is therefore crucial to improve the penumbra for proton pencil beam scanning. However, previous work has shown that collimation may not be necessary for depths of  >15 cm in water.
Winterhalter, Carla, Meier, Gabriel, Oxley, David, Weber, Damien C., Lomax, Antony J., Safai, Sairos   +5 more
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Multi-purpose nozzle for pencil beam scanning and wobbling

2009
PTCOG 48; Meeting of the Particle Therapy Co-Operative ...
Tachikawa, T, Ochi, T, Asaba, T, Yamada, M, Nishio, T, Ogino, T   +5 more
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Technical Note: Spot characteristic stability for proton pencil beam scanning a)

Medical Physics, 2016
Purpose:The spot characteristics for proton pencil beam scanning (PBS) were measured and analyzed over a 16 month period, which included one major site configuration update and six cyclotron interventions. The results provide a reference to establish the quality assurance (QA) frequency and tolerance for proton pencil beam scanning.Methods:A simple ...
Chin-Cheng, Chen, Chang, Chang, Michael F, Moyers, Mingcheng, Gao, Dennis, Mah   +4 more
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Clinical Pencil Beam Scanning: Present and Future Practices

2016
Pencil beam scanning (PBS) is the most advanced beam delivery technology in particle therapy nowadays. After a pioneering phase, PBS is rapidly becoming available on a larger scale worlwide, and is expected to be the standard beam delivery technique in the future to come.
Marco Schwarz, Carlo Algranati, Lamberto Widesott, Paolo Farace, Stefano Lorentini, Roberto Righetto, Daniele Ravanelli, Francesco Fracchiolla   +7 more
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Wind measurement resolution for a scanning pencil beam scatterometer

Proceedings of IGARSS '94 - 1994 IEEE International Geoscience and Remote Sensing Symposium, 2005
The problem of determining the effective wind measurement resolution of a wind scatterometer is considered. Using simplifying assumptions and approximations, a simple linear model for wind retrieval is derived and related to the effective wind estimate resolution and the backscatter measurement resolution.
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