The purpose of this study is to determine comparability of three different planar IMRT QA techniques: patient gantry angle composite (PGAC), single gantry angle composite (SGAC), and field by field (FBF), using MapCHECK 2 device and the γ test as performance metrics; and to assess the dependency of these techniques on intensity modulation, couch attenuation, and detector position (angular depen...

EPID images acquired in cine mode during arc therapy have inaccurate gantry angles recorded in their image headers. In this work, methods were developed to assess the accuracy of the gantry potentiometer for linear accelerators. As well, assessments of the accuracy of other, more accessible, sources of gantry angle information (i.e., treatment log files, analysis of EPID image headers) were inv...

MOTIVATION In this study, a method is reported to perform IMRT and VMAT treatment delivery verification using 3D volumetric primary beam fluences reconstructed directly from planned beam parameters and treatment delivery records. The goals of this paper are to demonstrate that 1) 3D beam fluences can be reconstructed efficiently, 2) quality assurance (QA) based on the reconstructed 3D fluences ...

OBJECTIVE This study was designed to optimize the scan protocol of CT angiography to reduce diaphragmatic motion artifacts in pediatric patients with free-breathing. MATERIALS AND METHODS A phantom with twelve tubes with different diameters was constructed. To simulate free-breathing, the phantom was connected to a motor, and the phantom moved along the axis of scan. Scans were performed unde...

PURPOSE The purpose of this work is to develop fast deliverable step and shoot IMRT technique. A reduction in the number of segments should theoretically be possible, whilst simultaneously maintaining plan quality, provided that the reduction is accompanied by an increased number of gantry angles. A benefit of this method is that the segment shaping could be performed during gantry motion, ther...

We consider topology based criteria for the selection of optimal beam orientations for conformal external radiotherapy. The advantage of such an approach is that computation time is considerably reduced since no dose calculation is required. The algorithm preclassifies all possible irradiation directions by assigning to each a fitness measure, the geometry fitness factor (GFF). This factor is a...

ID: 8177 Title: A Clinical Example of the Helical Tomotherapy Thread Effect: Robustness Discussion Purpose: A previous study explained why pitches of 0.86/n, where n is an integer, will provide the best junctioning of a helically delivered and diverging beam. The previous treatment was theoretical and based on unmodulated examples. In this study, a clinically relevant case of a palliative lung ...

The HICAT project is a Heavy Ion accelerator for light ion Cancer Treatment to be built for the clinics in Heidelberg, Germany. It consists of a 7 MeV/u linac, a compact synchrotron and three treatment places, one of them located after a 360 degree gantry beam-line. The facility will implement the intensity controlled rasterscanning technique that was developed and successfully demonstrated at ...

PURPOSE The authors propose a novel optimization model for volumetric modulated arc therapy (VMAT) planning that directly optimizes deliverable leaf trajectories in the treatment plan optimization problem, and eliminates the need for a separate arc-sequencing step. METHODS In this model, a 360° arc is divided into a given number of arc segments in which the leaves move unidirectionally. This ...