title: Reduction of organ motion by combined cardiac gating and respiratory gating.
abstract: OBJECTIVE
  To investigate whether the effect of organ motion can be further reduced with the application of a cardiac gating technique, together with respiratory gating.
  
  
  METHODS
  Axial and coronal images through the heart and liver were continuously scanned with fast cine magnetic resonance imaging scans at three different gating settings: (1) without respiratory and cardiac gating; (2) with respiratory gating, but without cardiac gating; and (3) with both respiratory and cardiac gating. The effect of motion for either the heart or liver was analyzed with probability maps.
  
  
  RESULTS
  With the application of respiratory gating only, the marginal region on the probability map was reduced by 10.0% in the axial slice and 19.8% in the coronal slice for the heart. It was reduced by 5.2% in the axial slice and 20.8% in the coronal slice for the liver. With the application of cardiac gating together with respiratory gating, the marginal region on the probability map was reduced further. The reduction was 8.0% in the axial slice and 13.6% in the coronal slice for the heart and 5.9% in the axial slice and 7.0% in the coronal slice for the liver.
  
  
  CONCLUSIONS
  The effect of organ motion can be further reduced with the application of cardiac gating together with respiratory gating. The potential application to treatment planning merits further investigation.
authors.affiliation: Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710, USA. zhiheng.wang@duke.edu
authors.forename: Zhiheng
authors.initials: Z
authors.lastname: Wang
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Willett
authors.forename: Fang-Fang
authors.initials: FF
authors.lastname: Yin
mesh_terms: D006321:Heart; D006801:Humans; D008099:Liver; D019028:Magnetic Resonance Imaging, Cine / Q000295:instrumentation / Q000379:methods*; D009068:Movement; D012119:Respiration