Patient-specific pretreatment verification of intensity-modulated radiation therapy (IMRT) or volumetric-modulated arc therapy (VMAT) is strongly recommended for all patients in order to detect any potential errors in treatment planning process and machine deliverability, and is thus performed routinely in many clinics. Portal dosimetry is an effective method for this purpose because of its pro...

Background: Image-guided radiotherapy used multiple imaging during the radiation therapy course to improve the precision and accuracy of health care provider's treatment. Objectives: This study aims to assess the safety, effectiveness and economic aspects of image-guided radiation therapy for decision-making about this technology in Iran. Methods: In this study, the most important med...

Electronic portal imaging devices (EPIDs) are potentially valuable tools for linear accelerator quality assurance and for measuring and analyzing geometric variations in radiation treatment delivery. Geometric analysis is more robust if referenced against an absolute position such as the isocenter (collimator axis of rotation), allowing the observer to discriminate between various setup errors ...

BACKGROUND This study was designed to compare the quality assurance (QA) results of four dosimetric tools used for intensity modulated radiation therapy (IMRT) and to suggest universal criteria for the passing rate in QA, irrespective of the dosimetric tool used. MATERIALS AND METHODS Thirty fields of IMRT plans from five patients were selected, followed by irradiation onto radiochromic film,...

PURPOSE To improve patient safety and treatment quality, verification of dose delivery in radiotherapy is desirable. We present a simple, easy-to-implement, open-source method for in vivo planar dosimetry of conformal radiotherapy by electronic portal imaging device (EPID). METHODS Correlation ratios, which relate dose in the mid-depth of slab phantoms to transit EPID signal, were determined ...

Photoinduced electron transitions can lead to significant changes of the macroscopic electronic properties in semiconductors. This principle is responsible for the detection of light with charge-coupled devices. Their spectral sensitivity is limited by the semiconductor bandgap which has restricted their visualization capabilities to the optical, ultraviolet, and X-ray regimes. The absence of a...

PURPOSE To use a graphic processing unit (GPU) calculation engine to implement a fast 3D pre-treatment dosimetric verification procedure based on an electronic portal imaging device (EPID). METHODS The GPU algorithm includes the deconvolution and convolution method for the fluence-map calculations, the collapsed-cone convolution/superposition (CCCS) algorithm for the 3D dose calculations and ...

Pretreatment dose verification with beam-by-beam analysis for intensity-modulated radiation therapy (IMRT) is commonly performed with a gantry angle of 0° using a 2D diode detector array. Any changes in multileaf collimator (MLC) position between the actual treatment gantry angle and 0° may result in deviations from the planned dose. We evaluated the effects of MLC positioning errors between th...

AIMS This study investigates the impact of cine acquisition mode on the dosimetric characteristics of a Varian aS500 amorphous silicon electronic portal imaging device (a-Si EPID). MATERIALS AND METHODS The performance of an a-Si EPID operated in cine mode was assessed and compared to its performance when operated in an integrated mode and dose measurements using an ionization chamber. This s...

Purpose To evaluate the Edose system, a novel three-dimensional (3D) in vivo dose monitoring system based on electronic portal imaging device (EPID), prior to clinical application, we analyzed the preliminary clinical data using Edose system in patients receiving intensity-modulated radiation therapy (IMRT). Materials and methods After the physical modeling, the measured results from the Edos...