RF and Microwave for Medical Applications
Predominantly RF applications are seen as only MRI scanners in Medicine, but the use of specialist technology at frequencies above UHF is quickly growing.
A number of examples of the applications are listed here.
- Vision Correction: RF energy is applied to the cornea to induce reshaping of the eye and adapt vision. The NearVisionSM CK® (Conductive Keratoplasty®) process achieves this without cutting any membrane.
- Liver Cancer:Tumors can be subjected to localised heating via RF to destroy cancer cells
MRI Scanning
At higher frequencies such as L band and X band localised application of radio frequency can be utilised for heating and cutting.
RF is used for wireless monitoring and machine to machine communication, connections to live implants for realtime monitoring and general RFID purposes.
Well known appliations are MRI. MRI scanner is a device in which the patient lies within a large, powerful magnet where the magnetic field is used to align the magnetization of some atomic nuclei in the body, and radio frequency magnetic fields are applied to systematically alter the alignment of this magnetization. This causes the nuclei to produce a rotating magnetic field detectable by the scanner—and this information is recorded to construct an image of the scanned area of the body.
Magnetic field gradients cause nuclei at different locations to precess at different speeds, which allows spatial information to be recovered using Fourier analysis of the measured signal. By using gradients in different directions, 2D images or 3D volumes can be obtained in any arbitrary orientation.
MRI provides good contrast between the different soft tissues of the body, which makes it especially useful in imaging the brain,muscles, the heart, and cancers compared with other medical imaging techniques such as computed tomography (CT) or X-rays.
