Results 171 to 180 of about 10,962 (218)

An electronic portal imaging device for transit dosimetry

Physics in Medicine and Biology, 1997
An electronic portal imaging device has been designed and constructed. It consists of an array of 128 CsI scintillation crystals coupled to photodiodes which is scanned across the field in 4 seconds. The linac is operated at a dose rate of 400 cGy min-1 and the dose delivered for image acquisition is approximately 27 cGy.
SymondsTayler, JRN, Partridge, M, Evans, PM   +2 more
openaire   +3 more sources

Automaticin vivoportal dosimetry of all treatments

Physics in Medicine and Biology, 2013
At our institution EPID (electronic portal imaging device) dosimetry is routinely applied to perform in vivo dose verification of all patient treatments with curative intent since January 2008. The major impediment of the method has been the amount of work required to produce and inspect the in vivo dosimetry reports (a time-consuming and labor ...
Van Herk, Marcel, Olaciregui-Ruiz, I, Rozendaal, R, Mijnheer, B, van Herk, M, Mans, A   +5 more
openaire   +4 more sources

Routine individualised patient dosimetry using electronic portal imaging devices

Radiotherapy and Oncology, 2007
To analyse the results of routine EPID measurements for individualised patient dosimetry.Calibrated camera-based EPIDs were used to measure the central field dose, which was compared with a dose prediction at the EPID level. For transit dosimetry, dose data were calculated using patient transmission and scatter, and compared with measured values ...
Sebastiaan M J J G, Nijsten, Ben J, Mijnheer, André L A J, Dekker, Philippe, Lambin, André W H, Minken   +4 more
openaire   +2 more sources

Breast in vivo dosimetry by a portal ionization chamber

Medical Physics, 2007
This work reports a practical method for the determination of the in vivo breast middle dose value, , on the beam central axis, using a signal , obtained by a small thimble ion chamber positioned at the center of the electronic portal imaging device, and irradiated by the x‐ray beam transmitted through the patient.
Grimaldi, Luca, D'Onofrio, Guido, Cilla, Savino, Fidanzio, Andrea, Stimato, Gerardina, Azario, Luigi, Deodato, Francesco, Macchia, Gabriella, MORGANTI, ALESSIO GIUSEPPE, Piermattei, Angelo   +9 more
openaire   +3 more sources

QA of dynamic MLC based on EPID portal dosimetry

Physica Medica, 2012
Dynamic delivery of intensity modulated beams (dIMRT) requires not only accurate verification of leaf positioning but also a control on the speed of motion. The latter is a parameter that has a major impact on the dose delivered to the patient. Time consumed in quality assurance (QA) procedures is an issue of relevance in any radiotherapy department ...
J, Richart, M C, Pujades, J, Perez-Calatayud, D, Granero, F, Ballester, S, Rodriguez, M, Santos   +6 more
openaire   +2 more sources

Characterization of a high-elbow, fluoroscopic electronic portal imaging device for portal dosimetry

Physics in Medicine and Biology, 1999
The application of a newly developed fluoroscopic (CCD-camera based) electronic portal imaging device (EPID) in portal dosimetry is investigated. A description of the EPID response to dose is presented in terms of stability, linearity and optical cross-talk inside the mechanical structure.
Boer, J.C.J. de, Heijmen, B.J.M., Pasma, K.L., Visser, A.G.   +3 more
openaire   +4 more sources

Transmission dosimetry with a liquid-filled electronic portal imaging device

International Journal of Radiation Oncology*Biology*Physics, 1996
To assess the accuracy of transmission dose rate measurements for various phantom-detector geometries, performed with an electronic portal imaging device (EPID) and to compare these transmission dose rate values with exit dose rate data.Transmission dose rate values on the central beam axis and beam profiles were measured with an EPID consisting of a ...
Essers, Marion, Boellaard, Ronald, Van Herk, Marcel, Lanson, Hugo, Mijnheer, Ben   +4 more
openaire   +3 more sources

Portal dosimetry for VMAT using integrated images obtained during treatment

Medical Physics, 2014
Purpose:Portal dosimetry provides an accurate and convenient means of verifying dose delivered to the patient. A simple method for carrying out portal dosimetry for volumetric modulated arc therapy (VMAT) is described, together with phantom measurements demonstrating the validity of the approach.Methods:Portal images were predicted by projecting dose ...
James L, Bedford, Ian M, Hanson, Vibeke Nordmark, Hansen   +2 more
openaire   +2 more sources

A literature review of electronic portal imaging for radiotherapy dosimetry

Radiotherapy and Oncology, 2008
Electronic portal imaging devices (EPIDs) have been the preferred tools for verification of patient positioning for radiotherapy in recent decades. Since EPID images contain dose information, many groups have investigated their use for radiotherapy dose measurement.
Wouter, van Elmpt, Leah, McDermott, Sebastiaan, Nijsten, Markus, Wendling, Philippe, Lambin, Ben, Mijnheer   +5 more
openaire   +2 more sources

An effective correction algorithm for off‐axis portal dosimetry errors

Medical Physics, 2009
Portal dosimetric images acquired for IMRT pretreatment verification show dose errors of up to 15% near the detector edges as compared to dose predictions calculated by a treatment planning system for these off‐axis regions. A method is proposed to account for these off‐axis effects by precisely correcting the off‐axis output factors, which calibrate ...
Daniel W, Bailey, Lalith, Kumaraswamy, Matthew B, Podgorsak   +2 more
openaire   +2 more sources