الفهرس 
Literature ReviewOnly 14 pages are availabe for public view
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Abstract
When IMRT treatment is considered to be a routine work, one should seek for an accurate, time
saving, fast and simple QA procedure. Electronic portal imaging device (EPlD), especially amorphous
silicon type, is a promising tool for lMRT dosimetry.
In this work a calibration of an amorphous silicon flat panel-type imager (Eiekta iViewGT, release
3.2) is done, which was incorrect (figure 3.1.) due to the EPID renormalization to the target value
(Eiekta instructions).
The calibration of the amorphous silicon flat panel-type imager (Elekta iViewGT) was repeated after
considering the Pixel Scaling Factor (PSF), which gave the correct response (figure 3.2.).
By using Omni Pro software the EPID images are converted into doses and a correction for the dose
reading from these images is done to obtain the same results as that measured at the isocenter in
20 em PMMA slab phantom. A correction for the EPID profiles for different field sizes is done to be
like those measured in the full scatter water phantom.
A pre-treatment verification for a clinical step & shoot IMRT plan is done for a prostate cancer
case generated by Xio (version 4.2.2) treatment planning system (TPS). The pre treatment
verification is done by EPID and a comparison in dose distribution against TPS and Films are
performed.
This study show that the combination between iViewGT and Omni Pro software with the corrections
provided in the present study gave an accurate method to verifY the dose of IMRT fields in two
dimensions inside a homogenous slab phantom.
The results indicated also that the EPID (Eiekta iViewGT ) is an accurate and can replace film for
field-by field pretreatment verification ofJMRT inside a phantom.