Background: As the volumetric modulated arc therapy (VMAT) becoming a main role of treatment ways, the effect of couch top becomes more significant. It is imperative to re-evaluate the couches that previously may have been considered of no importance during early treatment techniques. The impact of couch top on radiation delivery was explored and the couch model was tested with the aim of reduc...

PURPOSE We investigate the impact of a treatment couch and its modeling in a treatment planning system on accurate dose delivery in Volumetric Modulated Arc Therapy (VMAT). METHODS A cone-beam CT of a Varian couch on a Varian Clinac 21EX unit, consisting of a carbon-fiber imaging couch top and supporting rails, was acquired, and a couch model was created in Philips Pinnacle 9.0 TPS based on t...

The purpose of this study is to evaluate the accuracy and reproducibility of the IsoCal geometric calibration system for kilovoltage (kV) and megavoltage (MV) imagers on Varian C-series linear accelerators (linacs). IsoCal calibration starts by imaging a phantom and collimator plate using MV images with different collimator angles, as well as MV and kV images at different gantry angles. The sof...

A system and method for eliminating swing motions in gantry-style cranes while subject to operator control is presented. The present invention comprises an infinite impulse response ("IIR") filter and a proportional-integral ("PI") feedback controller (50). The IIR filter receives input signals (46) (commanded velocity or acceleration) from an operator input device (45) and transforms them into...

BACKGROUND The two-dimensional phantom dose verification (2D-PDV) using hybrid plan and planar dose measurement has been widely used for IMRT treatment QA. Due to the lack of information about the correlations between the verification results and the anatomical structure of patients, it is inadequate in clinical evaluation. A three-dimensional anatomical dose verification (3D-ADV) method was us...

One of the main advantages of the Gantry-Tau machine is a large accessible workspace/footprint ratio compared to many other parallel machines. The design presented in this paper achieves a workspace/footprint ratio of more than 2.7 with fixed length links, which is high for a PKM. Typical PKMs, for example the Delta robot, has a ratio less than one. Optimisation schemes are typically used in or...

We have demonstrated the first optically driven X-ray source based on carbon nanotube (CNT) photocathodes. It is a compact dual X-ray source and the two sources are accurately and independently controlled with two laser diodes illuminating the photocathodes. Thanks to the emission stability, high quality images have been obtained. This dual source provides two images from two different viewing ...

We present here a novel method for using a single device in the daily quality assur- ance (QA) of pencil beam scanning (PBS) proton beams and an improved method for uniform scanning (US). The device can be used to measure the spot position, spot sigma, range, output, collinearity of the X-ray system and proton beam, and to QA the first scatterers and a number of other imaging and mechanical che...

ID: 9678 Title: An analytical approach to prevent gantry-couch collision for linac-based radiosurgery Gantry-couch collision is a serious concern for the treatment planning of the linac-based stereotactic radiosurgery (SRS). The ability to detect collision at the planning time removes the need for backup plans and preserves the useful beam angles that would be deemed unsafe and discarded otherw...

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