Yes, EPID panels are indeed used for dose monitoring and quality assurance of the dose delivery to the patient [1][2]. However, this is relatively new in the industry and is not universal. The fact that EPIDs have become so common (since Varian and Elekta like to offer them as standard) means that this will be used more as time goes on.

As an aside, TLDs and IVD systems are falling out of favor for patient dose monitoring because AAPM TG 62 (referenced in the link in your other post) is not directly applicable to IMRT and VMAT modalities, which are pretty common these days.

[1]http://www.sunnuclear.com/medphys/patientqa/epidose/epidose....

[2]http://www.sunnuclear.com/snc_site/solutions/patientqa/perfr...