RF Transmitter · Electromagnetic
Designing the field that excites the spins, and accounting for the electric field that deposits power in the body.
The question
A transmit coil is designed for the magnetic field it produces, but it is limited by the electric field it cannot avoid. At higher field strengths the wavelength in tissue becomes comparable to the body, the transmit field stops being uniform, and the safety limit stops being a single number for the whole subject. Both effects have to be modelled, and the models have to be checked against measurement.
What we work on
- Full-wave models of transmit arrays, built so that the simulated coil matches the measured one closely enough to be used for safety prediction rather than illustration.
- Electric field measurement. Probes that measure the field directly, so the simulation has something to be wrong against.
- Heating around conductive implants, where the local field, not the global average, is what matters.