Objective: The measured dose was shown to be dependent on the angle of beam incidence and influenced by couch absorption when a 2D detector was used in a stationary phantom. The use of a 2D array (MatriXX) in combination with a solid water phantom (RW3) dose verification system was explored, which could take into account the couch absorption influences, generate correction factors (CFs) for each detector element, and also calibrate the measured dose for accurate validation of intensity-modulated arc therapy (IMAT) treatment plans. Methods: Based on the introduction of a homogeneous treatment bed model in the Monaco treatment planning system, CFs(theta) were constructed for all incidence angles using 6 MV photon lines in a 28 cm x 28 cm field for MatriXX at different field incidence angles (0 degrees -360 degrees) as a relative ratio of simulated and measured values. The accuracy of the 2D array in combination with the solid water phantom (MatriXX/RW3) was systematically investigated by verifying 12 IMAT plans with and without CFs. In addition, the resulting assessments were evaluated by 40 additional IMAT plans of different tumor sites, using the COMPASS three-dimensional (3D) dose validation device measurements as a benchmark. Results: After correction based on CFs(theta), the effect of the mean pass rates (3%/3 mm) of the MatriXX 2D array for 12 IMAT plan QA can be seenan explicit improvement of 6.1% was observed with the CFs(theta). The average pass rate increased from 92.0% to 98.1%, and the additional 40 IMAT plans QA gamma(3mm/3%) matched well between COMPASS and the measurements for MatriXX/RW3, with CFs(theta)'s of 98.4 +/- 1.5 vs. 99.1 +/- 0.9 for the phantom plans. For different tumor sites, the cervical, thoracic, and abdominal cases for the 3D COMPASS validation devices were 97.9 +/- 1.5 vs. 99.4 +/- 0.3, 99.1 +/- 0.9 vs. 98.6 +/- 1.6, and 98.7 +/- 0.9 vs. 99.3 +/- 0.7, respectively, with P = 0.051, 0.420, and 0.175. For head tumors, the 2D MatriXX validation pass rate was slightly lower than 3D COMPASS (97.7 +/- 2.0 vs. 99.2 +/- 0.5, P = 0.048). Conclusions: The combination of MatriXX with the solid water RW3 phantom and CFs(theta)'s incorporation of the main couch model (iBEAM evo Couchtop EP) proved to be a fast and reliable method for pre-treatment verification of arc therapy with sufficient accuracy. Slight deviations were found for patients with head tumors treated with the treatment bed extension plate assembly iBEAM (R) evo Extension 415. These could be minimized by constructing the extension plate couch model and then reconstructing the MatriXX/RW3 calibration factor.