The design of TMS coils determines the electric field pattern that is induced in the brain. Depending on the stimulation target, designs with various degrees of focality and field penetration depth could be desirable. We are interested in coil designs for deep brain stimulation, which are particularly challenging due to the rapid decay of electric field away from the coil. We are also exploring designs for “sham” (or “placebo”) coils with the objective to replicate all sensations associated with TMS except for stimulation of the brain. Sham coils are essential for properly controlled basic studies and clinical trials, however existing sham systems have significant shortcomings. In the process of coil development, we use finite element modeling (FEM) of electromagnetic fields with the software package MagNet from Infolytica Corporation which allows fast optimization of designs before a hardware prototype is constructed.
Deng, Z.-D., Peterchev, A. V., and Lisanby, S. H. (2008). Coil Design Considerations for Deep-Brain Transcranial Magnetic Stimulation (dTMS). Proc Internat Conf IEEE Eng Med Biol Soc: 5675-5679.
Ugawa, Y., Huang, Y.-Z., Sommer, M., Thickbroom, G., Hamada, M., Pascual-Leone, A., Paulus, W., Classen, J., Peterchev, A., Zangen, A. (2008). "Consensus: New Methodologies for Brain Stimulation." Brain Stimulation (accepted).