Devices, systems, and methods for applying tumor-treating fields

A treatment assembly for positioning on skin of a subject, the treatment assembly comprising:

• a plurality of electrode elements, each electrode element of the plurality of electrode elements comprising a metal layer, wherein each electrode element of the plurality of electrode elements has a skin-facing side that is configured to face the skin of the subject and an opposing, outer side that is configured to face away from the skin of the subject, wherein the plurality of electrode elements occupy an area;
• and
• a cover comprising a first layer of anisotropic material and at least one conductive adhesive or gel layer, the cover having:
• a first portion that is disposed over the plurality of electrode elements, wherein the first portion of the cover has a skin-facing side that contacts at least a first electrode element of the plurality of electrode elements, wherein the first portion of the cover comprises respective portions of each of the first layer of anisotropic material and the at least one conductive adhesive or gel layer;
• and
• a second portion that is positioned outwardly beyond the area occupied by the plurality of electrode elements;
• a base structure, wherein the base structure is positioned on the skin-facing side of the first portion of the cover such that the first portion of the cover overlies the base structure, wherein the base structure comprises a second layer of anisotropic material and at least one conductive adhesive or gel layer;
• and
• a thermal barrier layer positioned between the base structure and the first electrode element,
• wherein any contact between the cover and an electrode element of the plurality of electrode elements occurs by contact with a conductive adhesive or gel layer of the at least one conductive adhesive or gel layer of the cover, and
• wherein the first layer of anisotropic material and the second layer of anisotropic material each comprise a respective sheet of anisotropic material having a front face and a rear face, wherein:
• the sheet has a first thermal conductivity in a direction that is perpendicular to the front face, and thermal conductivity of the sheet in directions that are parallel to the front face is more than two times higher than the first thermal conductivity, or
• the sheet has a first resistance in a direction that is perpendicular to the front face, and resistance of the sheet in directions that are parallel to the front face is less than half of the first resistance.

A system comprising:

• a treatment assembly for positioning on skin of a subject, the treatment assembly comprising:
• a circuit board having a skin-facing side configured to face the skin of the subject, and an opposing, outer side configured to face away from the skin of the subject, wherein the circuit board has a perimeter;
• a plurality of electrode elements, each electrode element of the plurality of electrode elements comprising a metal layer coupled to the circuit board, wherein at least a first electrode element of the plurality of electrode elements is positioned on the outer side of the circuit board;
• and
• a cover comprising a layer of anisotropic material and at least one conductive adhesive or gel layer, the cover having:
• a first portion that is disposed over the first electrode element and the outer side of the circuit board, wherein the first portion of the cover contacts the first electrode element, wherein the first portion of the cover comprises respective portions of each of the layer of anisotropic material and the at least one conductive adhesive or gel layer;
• and
• a second portion that is positioned radially outside of the perimeter of the circuit board,
• wherein the cover comprises a layer of anisotropic material and at least one conductive adhesive or gel layer, and
• wherein any contact between the cover and an electrode element of the plurality of electrode elements occurs by contact with a conductive adhesive or gel layer of the at least one conductive adhesive or gel layer, and
• wherein the layer of anisotropic material comprises a sheet of anisotropic material having a front face and a rear face, wherein:
• the sheet has a first thermal conductivity in a direction that is perpendicular to the front face, and thermal conductivity of the sheet in directions that are parallel to the front face is more than two times higher than the first thermal conductivity, or
• the sheet has a first resistance in a direction that is perpendicular to the front face, and resistance of the sheet in directions that are parallel to the front face is less than half of the first resistance;
• and
• a current generator coupled to the treatment assembly.