title: Image quality and stability of image-guided radiotherapy (IGRT) devices: A comparative study.
abstract: BACKGROUND
  Our aim was to implement standards for quality assurance of IGRT devices used in our department and to compare their performances with that of a CT simulator.
  
  
  METHODS
  We investigated image quality parameters for three devices over a period of 16months. A multislice CT was used as a benchmark and results related to noise, spatial resolution, low contrast visibility (LCV) and uniformity were compared with a cone beam CT (CBCT) at a linac and simulator.
  
  
  RESULTS
  All devices performed well in terms of LCV and, in fact, exceeded vendor specifications. MTF was comparable between CT and linac CBCT. Integral nonuniformity was, on average, 0.002 for the CT and 0.006 for the linac CBCT. Uniformity, LCV and MTF varied depending on the protocols used for the linac CBCT. Contrast-to-noise ratio was an average of 51% higher for the CT than for the linac and simulator CBCT. No significant time trend was observed and tolerance limits were implemented.
  
  
  CONCLUSIONS
  Reasonable differences in image quality between CT and CBCT were observed. Further research and development are necessary to increase image quality of commercially available CBCT devices in order for them to serve the needs for adaptive and/or online planning.
authors.affiliation: Department of Radiotherapy, Medical University Vienna, Austria. Markus.Stock@akhwien.at
authors.forename: Markus
authors.initials: M
authors.lastname: Stock
authors.forename: Marlies
authors.initials: M
authors.lastname: Pasler
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Birkfellner
authors.forename: Peter
authors.initials: P
authors.lastname: Homolka
authors.forename: Richard
authors.initials: R
authors.lastname: Poetter
authors.forename: Dietmar
authors.initials: D
authors.lastname: Georg
mesh_terms: D016477:Artifacts; D003198:Computer Simulation; D054893:Cone-Beam Computed Tomography / Q000295:instrumentation* / Q000379:methods; D003287:Contrast Media; D004867:Equipment Design; D004869:Equipment Safety; D006801:Humans; D019047:Phantoms, Imaging; D018787:Radiation Oncology / Q000295:instrumentation / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000295:instrumentation* / Q000379:methods; D015641:Radiography, Interventional; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation; D011881:Radiotherapy, Computer-Assisted / Q000295:instrumentation*; D020266:Radiotherapy, Conformal / Q000295:instrumentation; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods; D017749:Total Quality Management
chemical_list: D003287:Contrast Media
references.citation: Int J Radiat Oncol Biol Phys. 2007 Mar 15;67(4):1229-37
references.pmid: 17336223
references.citation: Int J Radiat Oncol Biol Phys. 2008;71(1 Suppl):S48-52
references.pmid: 18406937
references.citation: J Appl Clin Med Phys. 2007 Jul 17;8(3):21-36
references.pmid: 17712297
references.citation: Int J Radiat Oncol Biol Phys. 2005 Jul 15;62(4):1239-46
references.pmid: 15913917
references.citation: Br J Radiol. 1981 Mar;54(639):221-31
references.pmid: 7470784
references.citation: Radiother Oncol. 2008 Jan;86(1):20-4
references.pmid: 18031854
references.citation: Med Dosim. 2006 Spring;31(1):62-70
references.pmid: 16551530
references.citation: Med Dosim. 2007 Summer;32(2):80-5
references.pmid: 17472886
references.citation: Int J Radiat Oncol Biol Phys. 1999 Oct 1;45(3):773-89
references.pmid: 10524434
references.citation: Med Phys. 2006 Nov;33(11):4431-47
references.pmid: 17153422
references.citation: Int J Radiat Oncol Biol Phys. 2008 Jan 1;70(1):75-82
references.pmid: 17869445
references.citation: Med Phys. 2008 May;35(5):1807-15
references.pmid: 18561655
references.citation: Int J Radiat Oncol Biol Phys. 2008;71(1 Suppl):S33-7
references.pmid: 18406934
references.citation: Phys Med Biol. 2008 Oct 7;53(19):5275-93
references.pmid: 18758000
references.citation: Int J Radiat Oncol Biol Phys. 2005 Nov 15;63(4):975-84
references.pmid: 16253772
references.citation: Med Phys. 2005 Aug;32(8):2673-81
references.pmid: 16193798
references.citation: Radiother Oncol. 2005 Jun;75(3):271-8
references.pmid: 15890419
references.citation: Int J Radiat Oncol Biol Phys. 2003 May 1;56(1):89-105
references.pmid: 12694827
references.citation: Med Phys. 2009 Jan;36(1):22-32
references.pmid: 19235370
references.citation: Med Phys. 1999 Dec;26(12):2635-47
references.pmid: 10619249