A study on dosimetric properties of electronic portal imaging device and its use as a quality assurance tool in Volumetric Modulated Arc Therapy

Abstract

The results provided a precise control of gantry speed, dose rate and leaf speeds during RapidArc delivery and were consistent over 6 weeks.

Risk assessment of a new acceptance testing procedure for conventional linear accelerators

“…The application of an EPID for quality assurance has continued to expand over the past decade. [18][19][20][21] Results of this study suggest that utilizing the EPID as a tool for more automated linac acceptance testing can reduce the number of high-priority errors occurring during machine acceptance. The reduction in equipment and steps needed to setup and perform an ATP test with automation led to a decrease in the failure modes present in an ATP test, and hence the failure pathways.…”

“…Several studies have demonstrated the EPID's applicability as a dosimetry verification tool for intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT). [18][19][20] More recently, the EPID was used to assess the submillimeter alignment of the table rotation with the MV isocenter. 21 The use for patient specific QA and submillimeter assessment demonstrates the reliability of the EPID when used correctly.…”

2D lag and signal nonlinearity correction in an amorphous silicon EPID and their impact on pretreatment dosimetric verification

“…The aS500 EPID has been shown to have a nonlinear signal response to radiation, 25,26,9,12 and the EPID's response over a range of doses relevant to IMRT was again measured in this work. Several open-field irradiations were delivered, and EPID images were acquired in "integrated image" mode, where the true pixel values were restored by multiplying the frame-averaged image by the number of frames.…”

A study on the correlation between plan complexity and gamma index analysis in patient specific quality assurance of volumetric modulated arc therapy

“…Measured dose plane in the phantom is then compared against the calculated dose using gamma evaluation first introduced by Low et al 4 Various detectors have been studied for IMRT and VMAT patient specific quality assurance. [5][6][7][8][9] Technological advancements have led to the use of new 3D dosimeters and metrics for patient specific QA. Such 3D gamma metric extends analysis into a third-dimensional axis, thereby providing full volumetric gamma assessment as an alternative to a single plane 2D gamma analysis.…”