title: SonoKnife: feasibility of a line-focused ultrasound device for thermal ablation therapy.
abstract: OBJECTIVE
  To evaluate the feasibility of line-focused ultrasound for thermal ablation of superficially located tumors.
  
  
  METHODS
  A SonoKnife is a cylindrical-section ultrasound transducer designed to radiate from its concave surface. This geometry generates a line-focus or acoustic edge. The motivation for this approach was the noninvasive thermal ablation of advanced head and neck tumors and positive neck nodes in reasonable treatment times. Line-focusing may offer advantages over the common point-focusing of spherically curved radiators such as faster coverage of a target volume by scanning of the acoustic edge. In this paper, The authors report studies using numerical models and phantom and ex vivo experiments using a SonoKnife prototype.
  
  
  RESULTS
  Acoustic edges were generated by cylindrical-section single-element ultrasound transducers numerically, and by the prototype experimentally. Numerically, simulations were performed to characterize the acoustic edge for basic design parameters: transducer dimensions, line-focus depth, frequency, and coupling thickness. The dimensions of the acoustic edge as a function of these parameters were determined. In addition, a step-scanning simulation produced a large thermal lesion in a reasonable treatment time. Experimentally, pressure distributions measured in degassed water agreed well with acoustic simulations, and sonication experiments in gel phantoms and ex vivo porcine liver samples produced lesions similar to those predicted with acoustic and thermal models.
  
  
  CONCLUSIONS
  Results support the feasibility of noninvasive thermal ablation with a SonoKnife.
authors.affiliation: Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA.
authors.forename: Duo
authors.initials: D
authors.lastname: Chen
authors.forename: Rongmin
authors.initials: R
authors.lastname: Xia
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
authors.forename: Gal
authors.initials: G
authors.lastname: Shafirstein
authors.forename: Peter M
authors.initials: PM
authors.lastname: Corry
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Griffin
authors.forename: Jose A
authors.initials: JA
authors.lastname: Penagaricano
authors.forename: Ozlem E
authors.initials: OE
authors.lastname: Tulunay-Ugur
authors.forename: Eduardo G
authors.initials: EG
authors.lastname: Moros
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D057086:High-Intensity Focused Ultrasound Ablation / Q000295:instrumentation*; D006801:Humans; D008954:Models, Biological