title: Asymmetric collimation can significantly reduce patient radiation dose during pulmonary vein isolation.
abstract: OBJECTIVE
  Current fluoroscopic and 3D image-guided treatment of atrial fibrillation (AF) by radiofrequency ablation is characterized by a substantial amount of X-ray radiation. We investigated the potential of an asymmetric collimation technique to reduce dose.
  
  
  RESULTS
  For 30 patients, referred for AF ablation, we determined the received fluoroscopy dose for various collimation scenarios: a single collimation window encompassing all veins as used in most labs (Sc 1), an optimal adjusted symmetric collimation window encompassing each two ipsilateral veins (Sc 2) or each individual vein (Sc 3) and an optimal asymmetric collimation window encompassing each two ipsilateral veins (Sc 4) or each individual vein (Sc 5). Twenty patients were studied retrospectively and 10 were studied prospectively. Total fluoroscopy effective dose for all collimation strategies amounted to 45 ± 31 mSv for a single collimation field (Sc 1), 36 ± 25 mSv (Sc 2), and 24 ± 14 mSv (Sc 3) for a symmetrically adjusted collimation window and 15 ± 10 (Sc 4) and 5 ± 3 mSv (Sc 5) for an asymmetrically adjusted collimation approach. Validation of symmetric (Sc 2) and asymmetric (Sc 4) collimation in 10 patients confirmed the retrospective analysis.
  
  
  CONCLUSIONS
  Implementation and effective application of an optimal asymmetric collimation approach would yield an average three- to nine-fold reduction of fluoroscopy dose during AF ablation procedures. This reduction exceeds what has been previously reported by implementing an electromagnetic catheter tracking approach. Furthermore, it can be easily integrated in the clinical workflow with limited additional one-time cost. Manufacturers of imaging systems should consider its implementation a priority, and physicians should adopt it in their workflow.
authors.affiliation: Department of Cardiology, University Hospital Gasthuisberg, University of Leuven, Leuven, Belgium. Stijn.DeBuck@uz.kuleuven.ac.be
authors.forename: Stijn
authors.initials: S
authors.lastname: De Buck
authors.forename: Andre
authors.initials: A
authors.lastname: La Gerche
authors.forename: Joris
authors.initials: J
authors.lastname: Ector
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Wielandts
authors.forename: Pieter
authors.initials: P
authors.lastname: Koopman
authors.forename: Christophe
authors.initials: C
authors.lastname: Garweg
authors.forename: Dieter
authors.initials: D
authors.lastname: Nuyens
authors.forename: Hein
authors.initials: H
authors.lastname: Heidbuchel
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D005260:Female; D005471:Fluoroscopy / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011667:Pulmonary Veins / Q000601:surgery*; D011829:Radiation Dosage; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome