PURPOSE Portal dose images acquired with an amorphous silicon electronic portal imaging device (EPID) suffer from artifacts related to backscattered radiation. The backscatter signal varies as a function of field size (FS) and location on the EPID. Most current portal dosimetry algorithms fail to account for the FS dependence. The ramifications of this omission are investigated and solutions fo...

PURPOSE To compare dosimetric and treatment delivery parameter differences between volumetric-modulated arc radiotherapy (VMAT) and intensity-modulated radiotherapy (IMRT) for large volume retroperitoneal sarcomas (RPS). MATERIALS AND METHODS Both VMAT and IMRT planning were performed on CT datasets of 10 patients with RPS who had been previously treated with preoperative radiotherapy. Plans ...

BACKGROUND We performed a clinical audit of preoperative rectal cancer treatment at two European radiotherapy centres (Poland and Spain). The aim was to independently verify adherence to a selection of indicators of treatment quality and to identify any notable inter-institutional differences. METHODS A total of 162 patients, in Catalan Institute of Oncology (ICO) 68 and in Greater Poland Can...

AIM The RapidArc commissioning and Acceptance Testing program will test and ensure accuracy in DMLC position, precise dose-rate control during gantry rotation and accurate control of gantry speed. BACKGROUND Recently, we have upgraded our linear accelerator capable of performing IMRT which was functional from 2007 with image guided RapidArc facility. The installation of VMAT in the existing l...

The ultimate check of the actual dose delivered to a patient in radiotherapy can only be achieved by using in vivo dosimetry. This work reports a pilot study to test the applicability of a thermoluminescent dosimetric system for performing in vivo entrance dose measurements in external photon beam radiotherapy. The measurements demonstrated the value of thermoluminescent dosimetry as a treatmen...

The American Association of Physicists in Medicine Task Group 119 instructed institutions to use a low-dose threshold of 10% or a region of interest determined by the jaw setting when they collected gamma analysis quality assurance (QA) data for the planar dose distribution. However, there are no clinical data to quantitatively demonstrate the impact of the low-dose threshold on the gamma index...