Low field NMR

The low-field magnetic resonance refers to the production of nuclear magnetic resonance by means of weak magnetic fields in the milli Tesla range. The principle applies in special forms of diagnostic imaging (magnetic resonance imaging, MRI), in the analysis ( magnetic resonance spectroscopy, MRS) and in therapeutic nuclear magnetic resonance. Studies show a diagnostic accuracy and high sensitivity in musculoskeletal imaging.

Properties

For the generation of nuclear spin resonance is required, a homogeneous magnetic field and a high-frequency alternating field in the high frequency range. If the field strength of the homogeneous magnetic field is smaller than in the order of 0.5 Tesla, refers to the resulting magnetic resonance as a low-field magnetic resonance.

Nuclear magnetic resonance, which are produced by magnetic fields in the range of 0.001 T to 0.1 T, are frequently also called ultra low-field magnetic resonance. Studies have shown that magnetic resonance can in principle be generated at field strengths down to the nano Tesla range into it. By comparison, the Earth's magnetic field has in Europe an amount of about 0.05 mT = 50,000 nT.

Areas of application

Low-field magnetic resonance imaging

Low-field magnetic resonance imaging is used in clinical imaging. The used field strengths for this application are mostly between 0.2 and 0.5 T. Compared to the high-field magnetic resonance imaging, the low-field magnetic resonance imaging has a lower signal - to-noise ratio, creating a less good resolution is caused and therefore higher sampling are required.

The advantages of this technique lie in the contrast differences that are better for different tissue types at smaller field strengths than at higher field strengths. Smaller magnetic field strengths also allow a smaller design. Thus, the use of MRI is much more pleasant for patients with klaustrophischer bias because the central opening of the MRTs can be chosen larger.

Low-field magnetic resonance imaging is considered to be an appropriate instrument to follow the course of disease and is mostly used because of the high contrast differences to study specific parts of the body (eg, wrist ).

An image construction is possible in principle even at magnetic field strengths in millitesla area.

Low-field NMR spectroscopy

Low-field NMR spectroscopy is used in analytical chemistry. This makes it possible to consider other relaxation processes than conventional NMR. The line width of NMR signal is scaled with the measured magnetic field. This leads to narrow line widths at small fields. For the detection of the signal SQUIDs ( superconducting quantum interference devices ) are used.

Therapeutic nuclear magnetic resonance

Another field of application of low-field magnetic resonance is the therapeutic nuclear magnetic resonance, should be treated with the painful changes in the musculoskeletal system.