title: Quality Control of Portal Imaging with PTW EPID QC PHANTOM.
abstract: OBJECTIVE
  Quality assurance (QA) and quality control (QC) of different electronic portal imaging devices (EPID) and portal images with the PTW EPID QC PHANTOM.
  
  
  METHODS
  Characteristic properties of images of different file formats were measured on Siemens OptiVue500aSi, Siemens BeamView Plus, Elekta iView, and Varian PortalVision and analyzed with the epidSoft 2.0 program in four radiation therapy centers. The portal images were taken with Kodak X-OMAT V and the Kodak Portal Localisation ReadyPack films and evaluated with the same program.
  
  
  RESULTS
  The optimal exposition both for EPIDs and portal films of different kind was determined. For double exposition, the 2+1 MU values can be recommended in the case of Siemens OptiVue500aSi Elekta iView and Kodak Portal Localisation ReadyPack films, while for Siemens BeamView Plus, Varian PortalVision and Kodak X-OMAT V film 7+7 MU is recommended.
  
  
  CONCLUSIONS
  The PTW EPID QC PHANTOM can be used not only for amorphous silicon EPIDs but also for images taken with a video-based system or by using an ionization chamber matrix or for portal film. For analysis of QC tests, a standardized format (used at the acceptance test) should be applied, as the results are dependent on the file format used.
authors.affiliation: Institute of Oncoradiology, Uzsoki Hospital, Budapest, Hungary. pesznyak@uzsoki.hu
authors.forename: Csilla
authors.initials: C
authors.lastname: Pesznyák
authors.forename: Gábor
authors.initials: G
authors.lastname: Fekete
authors.forename: Arpád
authors.initials: A
authors.lastname: Mózes
authors.forename: Balázs
authors.initials: B
authors.lastname: Kiss
authors.forename: Réka
authors.initials: R
authors.lastname: Király
authors.forename: István
authors.initials: I
authors.lastname: Polgár
authors.forename: Pál
authors.initials: P
authors.lastname: Zaránd
authors.forename: Arpád
authors.initials: A
authors.lastname: Mayer
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis / Q000379:methods / Q000592:standards; D005858:Germany; D019047:Phantoms, Imaging; D011785:Quality Assurance, Health Care / Q000379:methods* / Q000592:standards*; D011829:Radiation Dosage; D011874:Radiometry / Q000295:instrumentation* / Q000592:standards*; D014963:X-Ray Intensifying Screens