Читать книгу Essentials of MRI Safety - Donald W. McRobbie - Страница 106

The resonant length differs from 13 or 26 cm for most tissues at 1.5 and 3 T, and much broader resonant behavior is likely.

The final zone, is the far field or Fraunhofer region which occurs at distances much greater than a wavelength. In this region, we have fully formed electromagnetic plane waves whose intensity decreases with the inverse square law. Their intensity is measured as power density (in W m⁻²), but in MRI is very low – only relevant in terms of EM interference on other equipment.