Hyperthermia implants and a method and system for heating the implant

1 . A hyperthermia system for heating an implant in a tissue of a body, the system comprising:

at least one drive coil arranged to excite the implant with an alternating magnetic field;

at least one microwire, wherein the at least one microwire is arranged in a three-edged or four-edged tetrahedral shape; and

a magnetic field generator arranged to drive the alternating magnetic field or current through the at least one drive coil,

the implant comprising a heat source provided by at least one piece of magnetic material provided in the implant, the magnetic material exhibiting a large Barkhausen jump (LBJ) in its magnetization curve, and wherein the implant is configured to provide a uniform heating output from the implant that is independent of the orientation of the implant relative to the direction of the alternating magnetic field,

wherein excitation of the heat source at a frequency of 30-750 kHz provides hyperthermia treatment of a tissue surrounding the implant that is independent of an orientation of the implant with respect to a longitudinal axis of the alternating magnetic field.

2 . The hyperthermia treatment system of claim 1 wherein the at least one drive coil excites the implant below a switching field required to initiate bistable switching behavior of the magnetic material exhibiting a LBJ.

3 . The hyperthermia system of claim 1 , wherein the implant comprises a coiled microwire.

4 . The hyperthermia system of claim 3 , wherein the implant further comprises a microwire arranged along a longitudinal axis of the coiled microwire or wherein the coiled microwire is arranged along an axis.

5 . The hyperthermia treatment system of claim 1 , further comprising the implant, wherein the implant has a length, wherein the length is greater than or equal to 2 mm.

6 . A method of hyperthermia treatment comprising

implanting a hyperthermia implant in tissue of a human or animal body, the implant comprising at least one piece of magnetic material that exhibits a large Barkhausen jump (LBJ) in its magnetisation curve; and

exciting the implant with an alternating magnetic field to provide hyperthermia treatment to a tissue surrounding the implant, wherein the implant is configured to provide a magnitude of heating that is independent of an orientation of the implant with respect to a longitudinal axis of the alternating magnetic field.

7 . A hyperthermia system for heating an implant when implanted in a tissue of a body, the system comprising:

the implant configured to generate a heat output when excited by a magnetic field, the implant comprising at least one magnetic microwire, the at least one magnetic microwire being formed of a large Barkhausen jump material, wherein the at least one magnetic microwire comprises a plurality of wire portions; and

a magnetic field generator configured to generate the magnetic field having a direction of application, for exciting the implant in a sub-bistable mode;

wherein the plurality of wire portions are arranged with respect to one another such that during excitation, for all orientations of the implant with respect to the magnetic field, at least one of the wire portions defines an axis, which is angled by no more than 60° to the direction of application of the magnetic field, so that the implant provides a uniform heat output independent of its orientation.

8 . The hyperthermia system of claim 7 , wherein the implant further comprises a coiled microwire.

9 . The hyperthermia system of claim 8 , wherein the implant further comprises the at least one magnetic microwire arranged along a longitudinal axis of the coiled microwire.

10 . The hyperthermia system of claim 7 , wherein the at least one magnetic microwire is arranged in a three-edged or four-edged tetrahedral shape.

11 . The hyperthermia system of claim 7 , wherein the implant further comprises straight wire portions each having a length to diameter ratio of less than 100 or wherein one or more of the plurality of wire portions are straight wire portions each having a length to diameter ratio of less than 100.

12 . The hyperthermia system of claim 11 , wherein the straight wire portions each have a length of less than 25 mm, optionally less than 10 mm, or optionally less than 6 mm.

13 . The hyperthermia system of claim 7 , wherein the magnetic field generator is configured to generate the magnetic field at a frequency in the range 30-750 kHz.

14 . The hyperthermia system of claim 13 , wherein the magnetic field generator is configured to generate the magnetic field of a strength between 1000 A/m to 20,000 A/m at a frequency in the range 30-750 KHz.

15 . The hyperthermia system of claim 7 , wherein the at least one magnetic microwire comprises an iron-rich glass-coated amorphous microwire, a cobalt-rich glass-coated amorphous microwire, a nickel-rich glass-coated amorphous microwire, an iron-silicon-boron based amorphous microwire, an iron-based amorphous microwire, and/or a cobalt-based amorphous microwire.

16 . The hyperthermia system of claim 7 further comprising a temperature sensor and a controller, the temperature sensor being arranged to sense a temperature of the implant and to output to the controller, and the controller being configured to adjust the strength of the magnetic field in dependence on the sensed temperature.

17 . An implant for implanting in a tissue of a body, the implant comprising:

at least one magnetic microwire, the at least one magnetic microwire being formed of a large Barkhausen jump material;

wherein the implant is configured to generate a heat output when excited in a sub-bistable mode by a magnetic field having a direction of application; and

wherein the at least one magnetic microwire comprises a plurality of wire portions;

and wherein the plurality of wire portions are arranged with respect to one another such that during excitation, for all orientations of the implant with respect to the magnetic field, at least one of the wire portions defines an axis, which is angled by 60° or less to the direction of application of the magnetic field, in order that the implant provides a uniform heat output independent of its orientation.

18 . The implant of claim 17 , wherein the at least one microwire comprises three microwires forming three edges of a tetrahedron or a three-legged tripod, or comprises four microwires forming four edges of a tetrahedron.

19 . The implant of claim 17 , wherein the implant comprises less than 2 mg of the large Barkhausen jump material.

20 . A combined detection and hyperthermia system for locating and heating an implant when implanted in a tissue of a body, the combined system comprising:

the implant, wherein the implant has a length, wherein the length is greater than or equal to 2 mm;

a hyperthermia system comprising a magnetic field generator;

at least one sense coil arranged to detect a signal received from the implant; and

at least one detector associated with the at least one sense coil, the at least one detector configured to detect a harmonic response from the implant,

the magnetic field generator being configured to generate a first magnetic field at a first frequency between 1-100 kHz to excite the implant for locating the implant in the tissue, and to generate a second magnetic field at a second, higher, frequency between 30-750 kHz to excite the implant for providing the heat output, the magnetic field having a direction of application for exciting the implant in a sub-bistable mode.