Читать книгу Essentials of MRI Safety - Donald W. McRobbie - Страница 46

MRI incidents can lead to injury or death. The most frequent incidents are thermal, followed by mechanical, projectile, and hearing loss. We have considered the basic elements of MRI acquisitions, the components of the scanner and the magnetic fields encountered. There is a symmetry about the magnitude and time‐variance of the fields: B₀ is of the order of tesla; the imaging gradient fields a thousand times lower, typically milli‐tesla; B₁ is typically one thousand times less again, in micro‐tesla. At the same time the temporal variations range from zero to one hertz for movement in the static field, to kHz for the gradients, and MHz for B₁.

In the next chapter we consider the physical interactions of these fields with non‐biological matter. For those wishing to become MR Safety Experts, Chapter 2 should be read in conjunction with Appendix I supplemented by reading further reading of standard electromagnetism texts.