NMR/MRI
This technique involves the application of a powerful magnetic field to the body, and subsequent analysis of the way in which atoms within the body react to the field. It usually requires a prolonged period to obtain useful results, often several hours, and thus is not suited to real-time applications. While the performance can be increased greatly, the resolution is inherently low due to the difficulty of switching large magnetic fields quickly, and thus, while it may be suited in some cases to the original diagnosis, it is of only very limited use to us at present.