Results 121 to 130 of about 4,358 (152)

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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A Monte Carlo study on the collimation of pencil beam scanning proton therapy beams

Medical Physics, 2016
Purpose:The lateral edge of a proton therapy beam is commonly used to achieve conformality to the treatment volume where critical structures reside close to the target. However, when treating shallow depths, the lateral edge of a pencil beam scanning (PBS) system may be broader than that of a double scattered (DS) system.
Frances C, Charlwood, Adam H, Aitkenhead, Ranald I, Mackay   +2 more
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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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Dosimetric consequences of pencil beam width variations in scanned beam particle therapy

Physics in Medicine and Biology, 2013
Scanned ion beam delivery enables the highest degree of target dose conformation attainable in external beam radiotherapy. Nominal pencil beam widths (spot sizes) are recorded during treatment planning system commissioning. Due to changes in the beam-line optics, the actual spot sizes may differ from these commissioning values, leading to differences ...
M A, Chanrion, F, Ammazzalorso, A, Wittig, R, Engenhart-Cabillic, U, Jelen   +4 more
openaire   +2 more sources

Proton pencil beam scanning for mediastinal lymphoma: the impact of interplay between target motion and beam scanning

Physics in Medicine and Biology, 2015
The purpose of this study was to assess the feasibility of proton pencil beam scanning (PBS) for the treatment of mediastinal lymphoma. A group of 7 patients of varying tumor size (100-800 cc) were planned using a PBS anterior field. We investigated 17 fractions of 1.8 Gy(RBE) to deliver 30.6 Gy(RBE) to the internal target volume (ITV).
C, Zeng, J P, Plastaras, Z A, Tochner, B M, White, C E, Hill-Kayser, S M, Hahn, S, Both   +6 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. A diverse set of six clinical plans, representing various spot patterns and treatment sites, was used to ...
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 C, Meier G, Oxley D, Weber DC, Lomax AJ, Safai S   +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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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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