BACKGROUND We aimed to evaluate early clinical and pathological results for treating locally advanced rectal cancer with bevacizumab and neoadjuvant concurrent chemoradiotherapy using the technique of prone-position volumetric modulated arc therapy and to compare the toxicity of volumetric modulated arc therapy with that of supine-position four-field box radiotherapy. METHODS Twelve patients ...

In this study a novel, user-independent automated planning technique was developed to objectively compare volumetric modulated arc therapy (VMAT) and intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma planning, and to determine which technique offers a greater benefit for parotid-sparing and dose escalation strategies. Ten patients were investigated, with a standard prescripti...

We study the treatment plan optimization problem for volumetric modulated arc therapy (VMAT). We propose a new column-generation-based algorithm that takes into account bounds on the gantry speed and dose rate, as well as an upper bound on the rate of change of the gantry speed, in addition to MLC constraints. The algorithm iteratively adds one aperture at each control point along the treatment...

Volumetric-modulated arc therapy (VMAT) is considered to deliver a better dose distribution and to shorten treatment time. There is a lack of research regarding breast irradiation after breast-conserving surgery (BCS) using VMAT with prone positioning. We developed a new small-arc VMAT methodology and compared it to conventional (fixed-field) intensity-modulated radiation therapy (IMRT) in the ...

New calorimeters Simon Duane, NPL Calorimetry remains the most fundamental method for the measurement of absorbed dose and is the basis of almost all absorbed dose primary standards worldwide. Absorbed dose to water is realised either directly, by using water as the absorbing medium, or indirectly, by using another medium (usually graphite) and determining a factor to convert dose from that med...

Background: Recently we have upgraded our Varian Clinac 2100CD with a 6MV FFF beam, this upgrade being the first of its kind in our country. Even though the dosimetric characteristics of FFF beams have been reported both in experimental and Monte Carlo studies, application in planning and delivery is complex. The aim of this study was to validate the commissioning of upgraded FFF beams dosimetr...

Background: Aim of this study is to evaluate the accuracy of the gated volumetric modulated arc therapy (VMAT/RapidArc) using 2D planar dosimetry, DynaLog files and COMPASS 3D dosimetry system. Materials and Methods: Pre-treatment quality assurance of 10 gated VMAT plans was verified using 2D array and COMPASS 3D dosimetry system. Advantage of COMPASS over 2D planar is that it provides the clin...

BACKGROUND Textural features of edge-enhanced fluence were analysed to quantify modulation degree of volumetric modulated arc therapy (VMAT) plans. METHODS Twenty prostate and twenty head and neck VMAT plans were retrospectively selected. Fluences of VMAT plans were generated by integration of monitor units shaped by multi-leaf collimators (MLCs) at each control point. When generating fluence...