As1000 flat panel detector

All treatments in this work were delivered on a TrueBeam (Varian Medical System) with a Millennium 120‐leaf MLC using 6 megavoltage (MV) photon beams. An EPID (Varian aS1000 flat panel detector) was used to acquire MV integrated exit dose images. The detector has an area of 40 cm × 30 cm with a matrix of 1024 × 768 pixels, which provides a spatial resolution of 0.39 mm × 0.39 mm. The patient support was the QFIX (QFIX, Avondale, PA) replacement for the standard Varian couch top, which included the Dosemax couch insert and movable rails. Images were saved in the ARIA database in the same way as any patient treatment images. All images were measured at the source to detector distance (SDD) of 150 cm and were not scaled back to 100 cm SDD except for those in the MLC errors with IMRT test (Section 2.C.8) that were analyzed using PerFRACTION version2.

Measurements were performed with a Varian Trilogy Linac (Varian Medical Systems, Palo Alto, CA) equipped with a Millennium 120 multileaf collimators (MLC). The EPID detector (Varian aS1000 flat panel detector) was positioned at 150 cm source to detector distance, covering a field size of 40 × 30 cm² with a resolution of 1024 × 768 pixels. Dark and flood fields were acquired before the experiment. All measurements were performed using 6 MV X-rays and the acquisition software IAS3 (Image Acquisition System 3) and then processed with MATLAB (Math Work, Natick, MA). EPID images were captured using the integrated mode and the backscatter influence of the EPID support arm was removed [7 (link)].

The linac used in the study was a Varian Trilogy Linac (Varian Medical Systems, Palo Alto, CA) equipped with a Millennium 120 multileaf collimator (MLC). The EPID detector (Varian aS1000 flat panel detector) was located 50 cm below the isocentre and covered a field size of 40 cm × 30 cm with a resolution of 1024 × 768 pixels. Dark and flood fields were acquired before the experiment. All measurements were performed using 6 MV X-rays, and the acquisition software was Image Acquisition System 3 (IAS3). The MC environment used is PRIMO (version 0.3.64.1800).