Patent ID: 6496714
Filing Date: 2002-12-17
Classification: G01R

Abstract:
An RF-safe invasive device comprising at least one long conductor having a length which is greater than or equal to half the wavelength of the applied RF field generated an the object to be imaged by the RF signal energy transmitted during operation of a magnetic imaging apparatus used in conjunction with said RF-safe invasive device, wherein said device is to be introduced into the object being imaged and suppresses uncomfortable and dangerous heating of the device and the surrounding the object during the RF transmission, the RF-safe device further comprising:at least one series element of controllable impedance incorporated into said at least one long conductor, wherein said at least one series element is controlled by control signals to effectively subdivide the long conductor in electrical sections, said electrical sections being substantially shorter than half a wavelength of the RF applied by the magnetic resonance imaging apparatus as found in the tissue of the object being imaged, wherein heating in the at least one long conductor is avoided; a control unit defines one of a low (â€œonâ€ ) and a high impedance (â€œoffâ€ ) state of the series elements by generation of said control signals, wherein the control unit is controlled by the magnetic resonance imaging apparatus such that the series elements are operated in said high impedance state during RF transmission; and a control path that connects the control unit to the series elements.