Patient specific IMRT quality assurance with film, ionization chamber and detector arrays: Our institutional experience

•IMRT QA methods performed at our institution were analyzed retrospectively.•IMRT QA using film & ionization chamber was compared with 2D array of ion chambers.•Dosimetric measurements were compared against the plan based on multiple criteria.•Criteria included TPS, anatomic site, Linac type, number of control points, arcs or beams.•Average dose differences and Gamma analysis were estimated to exceed passing criteria.