title: Comparison of breathing gated CT images generated using a 5DCT technique and a commercial clinical protocol in a porcine model.
abstract: OBJECTIVE
  To demonstrate that a "5DCT" technique which utilizes fast helical acquisition yields the same respiratory-gated images as a commercial technique for regular, mechanically produced breathing cycles.
  
  
  METHODS
  Respiratory-gated images of an anesthetized, mechanically ventilated pig were generated using a Siemens low-pitch helical protocol and 5DCT for a range of breathing rates and amplitudes and with standard and low dose imaging protocols. 5DCT reconstructions were independently evaluated by measuring the distances between tissue positions predicted by a 5D motion model and those measured using deformable registration, as well by reconstructing the originally acquired scans. Discrepancies between the 5DCT and commercial reconstructions were measured using landmark correspondences.
  
  
  RESULTS
  The mean distance between model predicted tissue positions and deformably registered tissue positions over the nine datasets was 0.65 ± 0.28 mm. Reconstructions of the original scans were on average accurate to 0.78 ± 0.57 mm. Mean landmark displacement between the commercial and 5DCT images was 1.76 ± 1.25 mm while the maximum lung tissue motion over the breathing cycle had a mean value of 27.2 ± 4.6 mm. An image composed of the average of 30 deformably registered images acquired with a low dose protocol had 6 HU image noise (single standard deviation) in the heart versus 31 HU for the commercial images.
  
  
  CONCLUSIONS
  An end to end evaluation of the 5DCT technique was conducted through landmark based comparison to breathing gated images acquired with a commercial protocol under highly regular ventilation. The techniques were found to agree to within 2 mm for most respiratory phases and most points in the lung.
authors.affiliation: Department of Radiation Oncology, University of California Los Angeles, 200 Medical Plaza Suite B265, Los Angeles, California 90095.
authors.forename: Dylan P
authors.initials: DP
authors.lastname: O'Connell
authors.affiliation: Department of Radiation Oncology, University of California Los Angeles, 200 Medical Plaza Suite B265, Los Angeles, California 90095.
authors.forename: David H
authors.initials: DH
authors.lastname: Thomas
authors.affiliation: Department of Radiation Oncology, University of California Los Angeles, 200 Medical Plaza Suite B265, Los Angeles, California 90095.
authors.forename: Tai H
authors.initials: TH
authors.lastname: Dou
authors.affiliation: Department of Radiation Oncology, University of California Los Angeles, 200 Medical Plaza Suite B265, Los Angeles, California 90095.
authors.forename: James M
authors.initials: JM
authors.lastname: Lamb
authors.affiliation: Department of Radiation Oncology, University of California Los Angeles, 200 Medical Plaza Suite B265, Los Angeles, California 90095.
authors.forename: Franklin
authors.initials: F
authors.lastname: Feingold
authors.affiliation: Department of Radiation Oncology, University of California Los Angeles, 200 Medical Plaza Suite B265, Los Angeles, California 90095.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Low
authors.affiliation: Siemens Medical Solutions, USA, Inc., 600 North Wolfe Street, Baltimore, Maryland 21287.
authors.forename: Matthew K
authors.initials: MK
authors.lastname: Fuld
authors.affiliation: Department of Radiology, The University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 542242.
authors.forename: Jered P
authors.initials: JP
authors.lastname: Sieren
authors.affiliation: Department of Radiology, The University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 542242.
authors.forename: Chelsea M
authors.initials: CM
authors.lastname: Sloan
authors.affiliation: Department of Radiology, The University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 542242.
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Shirk
authors.affiliation: Department of Radiology, The University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 542242.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Hoffman
authors.affiliation: Siemens AG, Imaging and Therapy Division, Siemensstr. 1, Forchheim 91301, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Hofmann
mesh_terms: D000465:Algorithms; D000818:Animals; D008168:Lung / Q000000981:diagnostic imaging; D008297:Male; D023421:Models, Animal; D008954:Models, Biological; D009038:Motion; D011829:Radiation Dosage; D012119:Respiration; D055425:Respiratory-Gated Imaging Techniques / Q000295:instrumentation / Q000379:methods*; D013552:Swine; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*