title: Portal verification using the KODAK ACR 2000 RT storage phosphor plate system and EC films. A semiquantitative comparison.
abstract: OBJECTIVE
  The suitability of the storage phosphor plate system ACR 2000 RT (Eastman Kodak Corp., Rochester, MN, USA), that is destined for portal verification as well as for portal simulation imaging in radiotherapy, had to be proven by the comparison with a highly sensitive verification film.
  
  
  METHODS
  The comparison included portal verification images of different regions (head and neck, thorax, abdomen, and pelvis) irradiated with 6- and 15-MV photons and electrons. Each portal verification image was done at the storage screen and the EC film as well, using the EC-L cassettes (both: Eastman Kodak Corp., Rochester, MN, USA) for both systems. The soft-tissue and bony contrast and the brightness were evaluated and compared in a ranking of the two compared images. Different phantoms were irradiated to investigate the high- and low-contrast resolution. To account for quality assurance application, the short-time exposure of the unpacked and irradiated storage screen by green and red room lasers was also investigated.
  
  
  RESULTS
  In general, the quality of the processed ACR images was slightly higher than that of the films, mostly due to cases of an insufficient exposure to the film. The storage screen was able to verify electron portals even for low electron energies with only minor photon contamination. The laser lines were sharply and clearly visible on the ACR images.
  
  
  CONCLUSIONS
  The ACR system may replace the film without any noticeable decrease in image quality thereby reducing processing time and saving the costs of films and avoiding incorrect exposures.
authors.affiliation: Department of Radiotherapy and Radiooncology, University Hospital Carl Gustav Carus, University of Technology, 01307, Dresden, Germany. peter.geyer@mailbox.tu-dresden.de
authors.forename: Peter
authors.initials: P
authors.lastname: Geyer
authors.forename: Hilbert
authors.initials: H
authors.lastname: Blank
authors.forename: Horst
authors.initials: H
authors.lastname: Alheit
mesh_terms: D004583:Electrons; D006801:Humans; D008961:Models, Structural; D019047:Phantoms, Imaging; D017785:Photons; D013902:Radiography, Thoracic; D011868:Radioisotopes; D011879:Radiotherapy Dosage; D015203:Reproducibility of Results; D013687:Telencephalon / Q000000981:diagnostic imaging; D014962:X-Ray Film
chemical_list: D011868:Radioisotopes