medical implantable lead

Abstract

The present invention relates to a medical implantable lead having a coaxial structure, where an insulating tube arranged between an inner coil and an outer coil is provided with a periodically alternating capacitance along the length thereof in order to reduce lead tip heating during MRI scanning.

1 . A medical implantable lead, comprising an elongate coaxial arrangement of an outer coil, an inner coil and an intermediate insulating tube arranged between the outer coil and the inner coil, wherein the intermediate insulating tube has a periodically alternating capacitance along the length thereof. 
     
     
         2 . A medical implantable lead according to  claim 1 , wherein the intermediate insulating tube comprises a set of at least two segments, which set of at least two segments is repeated along the length of the intermediate insulating tube, and which segments have different capacitances, thereby providing the periodically alternating capacitance. 
     
     
         3 . A medical implantable lead according to  claim 2 , wherein the number of segments of each set is three. 
     
     
         4 . A medical implantable lead according to  claim 2 , wherein the length of each segment is shorter than or equal to 1/10 of the total length of the intermediate insulating tube. 
     
     
         5 . A medical implantable lead according to  claim 2 , wherein the segments are of equal length. 
     
     
         6 . A medical implantable lead according to  claim 2 , wherein the segments are individual parts which are arranged in engagement with each other. 
     
     
         7 . A medical implantable lead according to  claim 2 , wherein the intermediate insulating tube is made of silicone, where at least one segment in each set is doped with a dopant in order to provide a desired capacitance. 
     
     
         8 . A medical implantable lead according to  claim 7 , wherein the dopant is BaTiO 4 . 
     
     
         9 . A medical implantable lead according to  claim 1 , wherein the capacitance is varying continuously and periodically along the length of the intermediate insulating tube. 
     
     
         10 . A medical implantable lead according to  claim 9 , wherein the capacitance variation is provided by a varying concentration of a dopant. 
     
     
         11 . A medical implantable lead, comprising:
 first and second electrodes;   a coaxially configured inner coil and outer coil, the inner coil being coupled to the first electrode and the outer coil being coupled to the second electrode;   an intermediate insulating tube arranged between the outer coil and the inner coil, the intermediate insulating tube having a plurality of segments doped with one or more dopants to provide a periodic alternating capacitance along the length of the insulating tube.