The aim of the present study was to investigate the role of CTVision in interfractional setup errors during intensity-modulated radiation therapy (IMRT) in 12 nasopharyngeal carcinoma (NPC) patients. The trend of setup errors as a function of time during a fractionated radiotherapy course was investigated, and the influence of reconstructive thickness on image reconstruction for setup errors wa...

BACKGROUND The aim is to analyze characteristics and to study the potentials of non-coplanar intensity modulated radiation therapy (IMRT) techniques. The planning study applies to generalized organ at risk (OAR) - planning target volume (PTV) geometries. METHODS The authors focus on OARs embedded in the PTV. The OAR shapes are spherically symmetric (A), cylindrical (B), and bended (C). Severa...

PURPOSE Positional reproducibility in patients with prostate cancer fixed in the prone position with a set of immobilization devices for external-beam intensity-modulated radiation therapy (IMRT) was evaluated. In addition, the adequacy of our positional error reduction strategy and current planning target volume (PTV) margins was also evaluated. RESULTS Systematic error was corrected by the ...

Figure shows the absolute change in the Dmean for the anal sphincter (left y-axis) and relative change in the V64Gy for the rectal wall (right y-axis) expressed as a function of the relative increase in the homogeneity index HI of the dose distribution in the PTV. Conclusions: By increasing the inhomogeneity of the targeted dose to the PTV in prostate RT plans the dose delivered to the rectal w...

In this thesis a modular code skeleton for combining Variable Message Signs (VMS) and Adaptive Cruise Control (ACC) as a combined system are being presented. Basic control theory for the two control types are given with corresponding pseudo code. Also simulation with the different controllers are compared and discussed. Finally some tips and tricks regarding the simulation software VISSIM are g...

An external beam radiotherapy (EBRT) using megavoltage beam of linear accelerator is usually the treatment of choice in cancer patients. The goal of EBRT is to deliver the prescribed dose to the target volume, with as low as possible dose to the surrounding healthy tissue. A large number of procedures and different professions involved in radiotherapy, uncertainty of equipment and daily patient...

BACKGROUND AND PURPOSE Absolute dose measurements for Intensity Modulated Radiotherapy (IMRT) beamlets is difficult due to the lack of lateral electron equilibrium. Recently we found that the absolute dosimetry in the penumbra region of the IMRT beamlet, can suffer from significant errors (Capote et al., Med Phys 31 (2004) 2416-2422). This work has the goal to estimate the error made when measu...

INTRODUCTION Accurate localisation is an essential component for the delivery of intracranial stereotactic treatment. For fractionated stereotactic radiotherapy, we compared the daily localisation accuracy of a standard thermoplastic mask with a new maxillary fixation device (MFD). METHODS Daily pre-treatment kV cone-beam computed tomography (CBCT) scans of 23 patients (12 localised in the MF...

This work aimed at evaluating the performance of three different intensity-modulated radiotherapy (IMRT) treatment planning systems (TPSs)--KonRad, XiO and Prowess--for selected pediatric cases. For this study, 11 pediatric patients with different types of brain, orbit, head and neck cancer were selected. Clinical step-and-shoot IMRT treatment plans were designed for delivery on a Siemens ONCOR...

PURPOSE To present comparison of treatment plans made by using 2D and 3D methods in the planning system, as well as to assess the quality of treatment plans using the 2D and 3D methods. MATERIAL AND METHODS The studies involved a group of 31 patients with advanced lung cancer treated in the Brachytherapy Department of the Subcarpathian Cancer Center in Brzozów from 2011 to 2013. In total, 31 ...