نتایج جستجو برای: tired gantry

تعداد نتایج: 2824  

2015
Lifeng Zhu Kai Wei Wei Huan Wu

Gantry structure has the advantages of easy production, high bearing capacity, stability and so on. It is widely used in engineering. There is an optimal solution for different structural parameters in gantry. In the practical engineering application, the safety factor is higher, which can meet the load demand, and the weight is less. In this paper, the advantages and disadvantages of the colum...

2010
Ilya Tyapin Geir Hovland

One of the main advantages of the Gantry-Tau machine is a large accessible workspace/footprint ratio compared to many other parallel machines. The Gantry-Tau improves this ration further by allowing a change of assembly mode without internal link collisions or collisions between the links and end-effector. The reconfigurable Gantry-Tau kinematic design obtained by multi-objective optimisation a...

2015
Pejman Rowshanfarzad Peter Häring Hans L Riis Sune J Zimmermann Martin A Ebert

BACKGROUND In radiotherapy treatments, it is crucial to monitor the performance of linac components including gantry, collimation system, and electronic portal imaging device (EPID) during arc deliveries. In this study, a simple EPID-based measurement method is suggested in conjunction with an algorithm to investigate the stability of these systems at various gantry angles with the aim of evalu...

2010
John P. Mullins Michael G. Herman

Mechanical flex of the gantry and mounted imaging panels leads to systematic offsets in localization image isocenter as a function of gantry angle for linear accelerator-mounted image guidance systems. Subsequently, object positions obtained from localization radiographs may be offset, resulting in greater target positioning uncertainty. While current QA procedures measure kV/MV image agreement...

2012
Hideharu Miura Masayuki Fujiwara Masao Tanooka Hiroshi Doi Hiroyuki Inoue Yasuhiro Takada Norihiko Kamikonya Shozo Hirota

We compared the efficiency and accuracy of full-arc and half-arc volumetric-modulated arc therapy (VMAT) delivery for maxillary cancer. Plans for gantry rotation angles of 360° and 180° (full-arc and half-arc VMAT) were created for six maxillary cancer cases with the Monaco treatment planning system, and delivered using an Elekta Synergy linear accelerator. Full-arc and half-arc VMAT were compa...

2009
M. A. Ahmad

This paper presents the use of anti-sway angle control approaches for a two-dimensional gantry crane with disturbances effect in the dynamic system. Delayed feedback signal (DFS) and proportional-derivative (PD)-type fuzzy logic controller are the techniques used in this investigation to actively control the sway angle of the rope of gantry crane system. A nonlinear overhead gantry crane system...

2016
Andrew P. Santoso Kwang H. Song Yujiao Qin Stephen J. Gardner Chang Liu Indrin J. Chetty Benjamin Movsas Munther Ajlouni Ning Wen

BACKGROUND This study investigates the effect of gantry speed on 4DCBCT image quality and dose for the Varian On-Board Imager®. METHODS A thoracic 4DCBCT protocol was designed using a 125 kVp spectrum. Image quality parameters were evaluated for 4DCBCT acquisition using Catphan® phantom with real-time position management™ system for gantry speeds varying between 1.0 to 6.0°/s. Superior-inferi...

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