Imaging and Localizing Device Using the Barkhausen Effect



M. A. Shilov, Eric C. Frey, W. Paul Segars, Jingyan Xu and Benjamin M. W.Tsui



The objective of this research is to develop a reconstruction algorithm and software for a first-generation clinical prototype to image medical devices, such as fiducial markers, surgical clips, catheters, or stents, using the Barkhausen effect.



The Barkhausen effect occurs during the magnetization process of a ferromagnetic material and causes the material to become magnetized not continuously but in small steps. A large Barkhausen effect associated with rapid magnetic domain reversal along the wire is observed in amorphous materials when oscillating external magnetic field is applied. The rapid changes of the magnetic field around the wire caused by Barkhausen effect can be easily measured and can provide sufficient information for localizing the wire.

We propose to use the Barkhausen effect to locate and image medical devices. Such devices constructed from or incorporating amorphous ferromagnetic materials or coatings can be detected in a noninvasive manner with spatial resolutions as much as one-tenth of a millimeter at depths comparable to the diameter of the human body. An image data set would include the location, length, and diameter of such devices reconstructed with comparable accuracy.



We present the estimates of the spatial and angular resolutions of an imaging system based on the Barkhausen effect. We investigate the configuration and sufficient number of the magnetic detectors required to provide the desired accuracy of an amorphous wire location measurement.



Our preliminary results indicate that an imaging system based on Barkhausen effect can be used to localize amorphous ferromagnetic devices for radiation therapy purposes with sufficient accuracy and in reasonable time.



PHS Grant proposal  submitted