نتایج جستجو برای: volumetric modulated arc therapy

تعداد نتایج: 761818  

2017
Maria Cristina Righetti

The aim of this review is to summarize studies conducted by temperature-modulated differential scanning calorimetry (TMDSC) on polymer crystallization. This technique can provide several advantages for the analysis of polymers with respect to conventional differential scanning calorimetry. Crystallizations conducted by TMDSC in different experimental conditions are analysed and discussed, in or...

2017
Olha Shpotyuk Stanislaw Adamiak Elvira Bezvushko Jozef Cebulski Maryana Iskiv Oleh Shpotyuk Valentina Balitska

Light-curing volumetric shrinkage in dimethacrylate-based dental resin composites Dipol® is examined through comprehensive kinetics research employing nanoindentation measurements and nanoscale atomic-deficient study with lifetime spectroscopy of annihilating positrons. Photopolymerization kinetics determined through nanoindentation testing is shown to be described via single-exponential relaxa...

2016
William J. Beasley Alan McWilliam Adam Aitkenhead Ranald I. Mackay Carl G. Rowbottom

Contouring structures in the head and neck is time-consuming, and automatic seg-mentation is an important part of an adaptive radiotherapy workflow. Geometric accuracy of automatic segmentation algorithms has been widely reported, but there is no consensus as to which metrics provide clinically meaningful results. This study investigated whether geometric accuracy (as quantified by several comm...

Journal: :Optics express 2015
Firooz Aflatouni Behrooz Abiri Angad Rekhi Ali Hajimiri

An integrated silicon nanophotonic coherent imager (NCI), with a 4 × 4 array of coherent pixels is reported. In the proposed NCI, on-chip optical processing determines the intensity and depth of each point on the imaged object based on the instantaneous phase and amplitude of the optical wave incident on each pixel. The NCI operates based on a modified time-domain frequency modulated continuous...

2015
Vikren Sarkar Long Huang Prema Rassiah‐Szegedi Hui Zhao Jessica Huang Martin Szegedi Bill J. Salter

While modulated arc (mARC) capabilities have been available on Siemens linear accelerators for almost two years now, there was, until recently, only one treatment planning system capable of planning these treatments. The Eclipse treatment planning system now offers a module that can plan for mARC treatments. The purpose of this work was to test the module to determine whether it is capable of c...

2004
Sha X. Chang Timothy J. Cullip Katharin M. Deschesne Elizabeth P. Miller Julian G. Rosenman

Seven years of experience in compensator intensity-modulated radiotherapy (IMRT) clinical implementation are presented. An inverse planning dose optimization algorithm was used to generate intensity modulation maps, which were delivered via either the compensator or segmental multileaf collimator (MLC) IMRT techniques. The in-house developed compensator-IMRT technique is presented with the focu...

Journal: :Physics in medicine and biology 2008
Renzhi Lu Richard J Radke Jie Yang Laura Happersett Ellen Yorke Andrew Jackson

This paper presents a new algorithm for constrained intensity-modulated radiotherapy (IMRT) planning, made tractable by a dimensionality reduction using a set of plans obtained by fast, unconstrained optimizations. The main result is to reduce planning time by an order of magnitude, producing viable five field prostate IMRT plans in about 5 min. Broadly, the algorithm has three steps. First, we...

2012
Naoki Hayashi Yoichi Watanabe Ryan Malmin Hideki Kato

The purpose of this study was to evaluate the triple channel correction acquisition (TCCA) method for radiochromic film dosimetry performed with a flatbed scanner. The study had two parts: a fundamental and a clinical examination. In the fundamental examination, we evaluated the accuracy of calibration curves for Gafchromic EBT2 (EBT2). The films were calibrated using a field-by-field method wi...

2016
Farideh Farokhi Moghadam Hozan Mohammadi

Small photon field used in the intensity modulated radiotherapy (IMRT) and stereotactic radio surgery (SRS). It is difficult to measure beam profile and output factor because of electron disequilibrium, partial shutting of source because of this challenges, we need the good detector. This article is collection of 5 or more article and summary of the results of EBT3 that compared with EBT2 film ...

Journal: :Vision Research 2009
Ross Goutcher Gunter Loffler

Two luminance gratings of identical orientation and opposite directions of motion are seen as moving across one another (i.e. moving transparently) only if they differ in spatial frequency (SF) by a factor of four or more. Identical SF gratings produce counter-phase flicker. This suggests that opposite motions cancel each other at the level of motion detection. Here we show that motion transpar...

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