title: Theoretical design of a spherically sectioned phased array for ultrasound surgery of the liver.
abstract: OBJECTIVE
  The theoretical explanation of the limits of an array transducer to coagulate large tissues volumes.
  
  
  METHODS
  A theoretical model is used to illustrate the focal limitations of a spherically sectioned array designed for the treatment of deep seated tissue, e.g. liver. The design optimizes the acoustic dose as a function of the focal depth and available acoustic aperture with the goal of coagulating large volumes in a single sonication period. A quantitative measure of the possible region of focal necrosis is modeled as a function of array parameters with the limiting criteria being near field heating and patient pain.
  
  
  RESULTS
  Acoustic simulations show that the maximum distance to produce continuous necrosis between foci in a multiple focus pattern and in a temporally multiplexed pattern is approximately 50% larger than the distance needed between sequential foci.
  
  
  CONCLUSIONS
  Multiple focus patterns or rapidly scanned single foci are significantly advantageous to sequential sonications of a single focus transducer.
authors: MIT and Harvard Division of Health Sciences and Technology, Boston, MA, USA.
authors: D R
authors: DR
authors: Daum
authors: K
authors: K
authors: Hynynen
mesh_terms: D000465:Algorithms; D004867:Equipment Design; D006358:Hot Temperature; D006801:Humans; D008099:Liver / Q000473:pathology* / Q000601:surgery; D008954:Models, Biological; D009336:Necrosis; D010146:Pain / Q000209:etiology; D013499:Surface Properties; D014159:Transducers; D014464:Ultrasonic Therapy / Q000295:instrumentation*; D014465:Ultrasonics