Abstract
We present a method to calculate the electric (E)-fields within and surrounding a human body in a gradient coil, including E-fields induced by the changing magnetic fields and "conservative" E-fields originating with the scalar electrical potential in the coil windings. In agreement with previous numerical calculations, it is shown that magnetically-induced E-fields within the human body show no real concentration near the surface of the body, where nerve stimulation most often occurs. Both the magnetically-induced and conservative E-fields are shown to be considerably stronger just outside the human body than inside it, and under some circumstances the conservative E-fields just outside the body can be much larger than the magnetically-induced E-fields there. The order of gradient winding and the presence of conductive RF shield can greatly affect the conservative E-field distribution in these cases. Though the E-fields against the outer surface of the body are not commonly considered, understanding gradient E-fields may be important for reasons other than peripheral nerve stimulation (PNS), such as potential interaction with electrical equipment.
Original language | English (US) |
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Pages (from-to) | 1424-1432 |
Number of pages | 9 |
Journal | Magnetic resonance in medicine |
Volume | 55 |
Issue number | 6 |
DOIs | |
State | Published - Jun 2006 |
Keywords
- Calculations
- Electric fields
- Gradient coil
- Peripheral nerve stimulation
- Scalar potential
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging