Magnetic field detectors include a proof mass suspended by deformable arms similar to a three dimensional accelerometer. The magnetic field detectors further include magnetically sensitive material present on the proof mass and/or deformable arms to cause movement of the proof mass and/or deformable arms when in the presence of a magnetic field. This movement is converted to an electrical signal and that electrical signal is compared to a reference to determine if a magnetic field of interest is present. The magnetic field detector may be included within an implantable medical device, and when the magnetic field detector indicates that a magnetic field of an MRI scanner is present, the implantable medical device may switch to an MRI mode of operation. The device may also switch back to a normal mode of operation once the MRI scanner is no longer detected such as after a predefined amount of time.

An implantable magnet that can freely turn in response to an external magnetic field, thus avoiding torque and demagnetization on the implantable magnet. The implantable magnet can be combined with an electric switching function depending on the orientation of an external magnetic field, thus protecting an implanted coil and/or implant electronics against induction of over-voltage or performing an electric switching function for other various purposes. The magnetic switch may further include, for example, a first switching contact and a second switching contact. A magnetically soft body that includes an electrically conductive surface is shiftable between a first position where the body is in simultaneous contact with the first and second switching contacts, and a second position where the body is out of contact with at least one of the first and second switching contacts. The body and the implantable magnet are positioned such that the body is shifted to one of the first position and the second position as a function of the external magnetic field resulting in a magnetic force between the magnet and the magnetically soft body.

Implantable medical devices include a first sensor for detecting a magnetic field that indicates an exposure mode of operation is appropriate. The implantable medical devices include a second sensor for detecting whether an MRI characteristic is present that indicates whether MRI or non-MRI post exposure diagnostics and other actions should be implemented and may also indicate whether the exposure mode should be MRI or non-MRI specific. An MRI post exposure diagnostic may perform pacing capture threshold tests and the post exposure pacing amplitude output may be kept at a higher than normal level. The second sensor may be an overvoltage clamp circuit of a telemetry coil that indicates whether an overvoltage condition on the telemetry coil is occurring to indicate whether an MRI characteristic is present. The second sensor may be a second threshold magnetic sensor, an accelerometer, or a microphone to indicate whether an MRI characteristic is present.

Radiopaque markers represent that a lead is suitable for a particular medical procedure such as a magnetic resonance image scan and are added to the lead or related device. The markers may be added after implantation of the lead in various ways including suturing, gluing, crimping, or clamping a radiopaque tag to the lead or to the device. The markers may be added by placing a radiopaque coil about the lead, and the radiopaque coil may radially contract against the lead to obtain a fixed position. The markers may be added by placing a polymer structure onto the lead where the polymer structure includes a radiopaque marker within it. The polymer structure may include a cylindrical aperture that contracts against the lead to fix the position of the polymer structure. The polymer structure may form a lead anchor that includes suture wings that can be sutured to the lead.

A medical system for performing a therapeutic function on a patient comprises an implantable medical device having a switching function to switch from a normal operating mode to an MRI compatible operating mode in the presence of an MRI device, and an external device for programming at least one setting of the implantable medical device. The external device is configured, based on a programming event relating to said at least one setting, to generate a notification prompting a user to confirm a continuing MRI compatibility of said MRI compatible operating mode after the programming event and/or to amend said at least one setting for achieving MRI compatibility.

The present invention changes the magnet-mode of an active implantable medical device (AIMD) using a static strip magnet comprising at least a first, second and third magnet. The electronic circuits of the AIMD have been programmed to register when the static strip magnet has been swiped across the AIMD so that when the magnetic field-detection sensor detects a defined north and south polarity sequence of the first, second and third magnets, the electronic circuits have been programmed to enter into magnet-mode with electrical stimulation therapy of the body tissue and/or electrical sensing of biological signals from the body tissue being suspended, maintained in a preset mode, or placed in a programmed mode.

Apparatus and methods for controlling a radiotherapy electron beam. Exemplary embodiments provide for focusing the electron beam at different depths by altering parameters of a plurality of magnets. Exemplary embodiments can also provide for focusing the electron beam at different depths while maintaining the energy level of the electron beam at a consistent level.

Embodiments describe herein generally pertain to implantable medical device (IMDs), and methods for use therewith, that can be used to automatically switch an IMD from its normal operational mode to magnetic resonance imaging (MRI) safe mode, and vice versa, within increased specificity. A controller of an IMD is configured to use an accelerometer to determine whether a positional condition associated with a patient is detected, and control sampling of a magnetic field sensor or at least one signal output therefrom, such that a first sampling rate is used when the positional condition is detected, and a second sampling rate, that is slower than the first sampling rate, is used when the positional condition is not detected, to thereby conserve power. Based on results of the sampling, the controller determines whether a magnetic field condition is detected, and in response thereto performs a mode switch to an MRI safe mode.

Implantable medical devices automatically switch from a normal mode of operation to an exposure mode of operation and back to the normal mode of operation. The implantable medical devices may utilize hysteresis timers in order to determine if entry and/or exit criteria for the exposure mode are met. The implantable medical devices may utilize additional considerations for entry to the exposure mode such as a confirmation counter or a moving buffer of sensor values. The implantable medical devices may utilize additional considerations for exiting the exposure mode of operation and returning to the normal mode, such as total time in the exposure mode, patient position, and high voltage source charge time in the case of devices with defibrillation capabilities.

This disclosure provides methods and apparatus for wirelessly transferring power. A first aspect of this disclosure is an apparatus for receiving power wirelessly. The apparatus comprises a receive circuit configured to receive wireless communication and charging power. The apparatus also comprises a metallic structure defining a gap extending from a first surface to a second surface, and through the metallic structure, the first surface opposite the second surface. The metallic structure is configured to receive the charging power from a wireless charging field oscillating at a first frequency. The metallic structure is further configured to convey the received power to the receive circuit via first and second connecting feeds. The metallic structure is also further configured to shield the receive circuit from interference at frequencies other than the first frequency.