title: Heat transfer due to electroconvulsive therapy: Influence of anisotropic thermal and electrical skull conductivity.
abstract: OBJECTIVE
  This paper focuses on electroconvulsive therapy (ECT) and head models to investigate temperature profiles arising when anisotropic thermal and electrical conductivities are considered in the skull layer. The aim was to numerically investigate the threshold for which this therapy operates safely to the brain, from the thermal point of view.
  
  
  METHODS
  A six-layer spherical head model consisting of scalp, fat, skull, cerebro-spinal fluid, grey matter and white matter was developed. Later on, a realistic human head model was also implemented. These models were built up using the packages from COMSOL Inc. and Simpleware Ltd. In these models, three of the most common electrode montages used in ECT were applied. Anisotropic conductivities were derived using volume constraint and included in both spherical and realistic head models. The bio-heat transferring problem governed by Laplace equation was solved numerically.
  
  
  RESULTS
  The results show that both the tensor eigenvalues of electrical conductivity and the electrode montage affect the maximum temperature, but thermal anisotropy does not have a significant influence. Temperature increases occur mainly in the scalp and fat, and no harm is caused to the brain by the current applied during ECT.
  
  
  CONCLUSIONS
  The work assures the thermal safety of ECT and also provides a numerical method to investigate other non-invasive therapies.
authors.affiliation: School of Mechanical and Electrical Engineering, University of Southern Queensland, Toowoomba, Queensland 4350, Australia. Electronic address: Marilia.MenezesDeOliveira@usq.edu.au.
authors.forename: Marilia
authors.initials: M
authors.lastname: Menezes de Oliveira
authors.affiliation: School of Mechanical and Electrical Engineering, University of Southern Queensland, Toowoomba, Queensland 4350, Australia.
authors.forename: Peng
authors.initials: P
authors.lastname: Wen
authors.affiliation: School of Mechanical and Electrical Engineering, University of Southern Queensland, Toowoomba, Queensland 4350, Australia.
authors.forename: Tony
authors.initials: T
authors.lastname: Ahfock
mesh_terms: D004565:Electroconvulsive Therapy; D004566:Electrodes; D006358:Hot Temperature; D006801:Humans; D008953:Models, Anatomic; D012886:Skull / Q000502:physiology*
keywords: Anisotropy; ECT; Finite element method; Head model; Temperature