Transducer array for tumor therapy electric field (ttfield) therapy using dedicated flexible circuits

Abstract

An alternating electric field (e.g., a tumor therapy electric field or TTField) may be applied to a subject's body using a device (e.g., a transducer array) that includes: a first PCB having a metal pad and configured to couple an AC signal into the subject's body at a high current; and a second low cost PCB that can only handle a lower current. The first PCB is located at a central portion of the device and the second PCB is located at a peripheral portion of the device. A temperature sensor (e.g., a thermistor) is electrically connected to the second PCB. In some embodiments, the second PCB is substantially larger than the first PCB.

Description

[0001] Cross-reference to related applications This application claims the benefit of U.S. Provisional Application 63 / 541419, filed September 29, 2023, the entire contents of which are incorporated herein by reference. Background Technology

[0002] Tumor therapeutic electric fields (TTField) therapy is a proven cancer treatment method that uses an alternating electric field with a frequency, for example, between 50 kHz and 5 MHz (more commonly 100 kHz to 500 kHz). Traditionally, the alternating electric field is induced by electrode assemblies (e.g., an array of capacitively coupled electrodes, also known as a transducer array) placed on the skin of the subject on opposite sides of the body. When an AC voltage is applied between the opposing electrode assemblies, an AC current is coupled through the electrode assemblies and enters the subject's body. Higher currents are closely associated with higher therapeutic efficacy.

[0003] Alternating electric fields can also be used to treat medical conditions other than cancer. For example, as described in U.S. Patent No. 10,967,167, an alternating electric field, for example, at 75 kHz to 150 kHz, can be used to increase the permeability of the blood-brain barrier (BBB), allowing, for example, chemotherapy drugs to enter the brain.

[0004] An example of a prior art electrode assembly that can be used to apply an alternating electric field to a subject's body is the electrode assembly described in U.S. Patent 8,715,203. This electrode assembly includes nine electrode elements, each comprising: (a) a metal layer; and (b) a ceramic layer positioned between the metal layer and the subject's skin, having a very high dielectric constant. A thermistor is included in a small aperture positioned at the center of most of the electrode elements for temperature measurement at these electrode elements.

[0005] Another example of a prior art electrode assembly that can be used to apply an alternating electric field to a subject's body is the electrode assembly described in U.S. Publication No. 2021 / 0402179. These electrode assemblies have a flexible circuit including multiple conductive pads on the front side of the flexible circuit and multiple flexible polymer regions disposed on and in front of the conductive pads. Multiple thermistors positioned on the rear side of the flexible circuit in thermal contact with the respective conductive pads are used to sense the temperature of the conductive pads.

[0006] To use any of these prior art electrode assemblies, an AC voltage is applied to the metal layer of the electrode element in the opposing electrode assembly to generate a TTField within the subject's body. During use, the skin beneath the electrode element heats up, creating a set of warmer spots directly beneath the electrode element and a set of cooler areas directly beneath the space between the electrode elements. Furthermore, these hot spots limit the amount of current that can be delivered through the prior art electrode assemblies because safety considerations require the skin temperature to remain below a safety threshold (e.g., 41°C). More specifically, prior art systems rely on a signal from a thermistor to ensure the current is low enough to prevent the subject's skin temperature from exceeding the safety threshold. Summary of the Invention

[0007] One aspect of the present invention relates to a first device for applying an electrical signal to a subject's body. The first device includes a first PCB, a second PCB, and a plurality of temperature sensors. The first PCB has a first substrate and at least one metal pad disposed on the skin-facing side of the first substrate. The second PCB has a second substrate and a plurality of conductive traces, and the second PCB is flexible. Each of the plurality of temperature sensors is electrically connected to at least one of the conductive traces of the second PCB. The first PCB has an outer boundary, and the first PCB and the second PCB are positioned such that, when viewed from a direction perpendicular to the first PCB, the second PCB lies outside the outer boundary of the first PCB.

[0008] Some embodiments of the first device also include a flexible backing positioned behind the first PCB and the second PCB. The flexible backing is configured to support the first PCB and the second PCB, and at least a portion of the flexible backing extends laterally beyond both the first PCB and the second PCB and is covered with a skin-adhesive biocompatible adhesive. The first PCB is flexible, and the plurality of conductive traces on the second PCB are formed using conductive ink. Optionally, in these embodiments, the first PCB has a first area, the second PCB has a second area, and the second area is larger than the first area.

[0009] Some embodiments of the first device further include a flexible backing positioned behind the first PCB and the second PCB. The flexible backing is configured to support the first PCB and the second PCB, and at least a portion of the flexible backing extends laterally beyond both the first PCB and the second PCB and is covered with a skin-adhesive biocompatible adhesive. The first PCB is flexible, and the plurality of conductive traces on the second PCB are formed using conductive ink. These embodiments further include: a first conductive adhesive or conductive gel layer disposed on and in front of both the first PCB and the second PCB; an anisotropic material layer disposed on and in front of the first conductive adhesive or conductive gel layer; and a second conductive adhesive or conductive gel layer disposed on and in front of the anisotropic material layer.

[0010] Optionally, in the embodiments described in the preceding paragraph, the anisotropic material layer comprises graphite. Optionally, in the embodiments described in the preceding paragraph, the anisotropic material layer comprises a pyrolytic graphite layer, a graphitized polymer film, or a graphite foil made from compressed, high-purity exfoliated mineral graphite. Optionally, the embodiments described in the preceding paragraph may further include at least one dielectric material layer disposed in front of (optionally disposed on and in front of) the at least one metal pad, and the dielectric constant of the at least one dielectric material layer is at least 10. Optionally, in the embodiments described in the preceding paragraph, the first PCB further includes at least one dielectric material layer disposed on and in front of the at least one metal pad, and the dielectric constant of the at least one dielectric layer is at least 10. Optionally, each metal pad in the later embodiments may be copper.

[0011] Some embodiments of the first device also include a connector that is fixed to the second PCB. Furthermore, the plurality of temperature sensors, the plurality of conductive traces on the second PCB, and the connector are positioned and arranged such that temperature readings obtained using the plurality of temperature sensors can be accessed via the connector.

[0012] In some embodiments of the first device, the first PCB has a first area, the second PCB has a second area, and the second area is at least twice the size of the first area.

[0013] In some embodiments of the first device, the first substrate and the second substrate partially or completely overlap each other in an overlap area and are laminated together in the overlap area. In some embodiments of the first device, the first substrate and the second substrate are the same substrate, or the first substrate and the second substrate are coplanar.

[0014] In some embodiments of the first device, the plurality of temperature sensors includes at least two temperature sensors, at least three temperature sensors, or at least four temperature sensors.

[0015] Another aspect of the invention relates to a second device for applying electrical signals to a subject's body. The second device includes a flexible PCB, at least two temperature sensors, a first conductive adhesive or conductive gel layer, and a flexible backing. The flexible PCB has a central segment and a peripheral segment located outside the outer boundary of the central segment, and the PCB has at least one metal pad disposed on the skin-facing side of the central segment of the PCB, and a plurality of conductive traces. Each of the at least two temperature sensors is mounted to the peripheral segment of the PCB and electrically connected to at least one of the conductive traces. The first conductive adhesive or conductive gel layer is disposed on and on the front of the PCB. Furthermore, the flexible backing is positioned behind the PCB. The flexible backing is configured to support the PCB, and at least a portion of the flexible backing extends laterally beyond the PCB and is covered with a biocompatible adhesive that adheres to the skin. In some embodiments, the second device includes at least three or at least four temperature sensors.

[0016] In some embodiments of the second device, the central section of the flexible PCB is defined by a bump that surrounds the perimeter of the outermost metal pad of the at least one metal pad.

[0017] Some embodiments of the second device further include: an anisotropic material layer disposed on and in front of the first conductive adhesive or conductive gel layer, wherein the area of ​​the anisotropic material layer is at least twice the area of ​​the central segment; and a second conductive adhesive or conductive gel layer disposed on and in front of the anisotropic material layer.

[0018] Optionally, in the embodiments described in the preceding paragraph, the anisotropic material layer comprises graphite. Optionally, in the embodiments described in the preceding paragraph, the anisotropic material layer comprises a pyrolytic graphite layer, a graphitized polymer film, or a graphite foil made of compressed, high-purity exfoliated mineral graphite.

[0019] Some embodiments of the second device further include at least one dielectric material layer disposed in front of the at least one metal pad. The dielectric constant of the at least one dielectric material layer is at least 10.

[0020] In some embodiments of the second device, the PCB further includes at least one dielectric material layer disposed on and in front of the at least one metal pad, and the dielectric constant of the at least one dielectric material layer is at least 10. In some embodiments of the second device, each conductive trace in the peripheral segment of the at least two temperature sensors connected to the plurality of conductive traces is formed using conductive ink. In some embodiments of the second device, each of the metal pads is a copper pad. In some embodiments of the second device, none of the metal pads are located in the peripheral segment of the PCB.

[0021] Another aspect of the invention relates to a third device for applying an electrical signal to a subject's body. The third device includes a first PCB, a second PCB, a plurality of temperature sensors, and a flexible backing. The first PCB has a first substrate and at least one metal pad disposed on the skin-facing side of the first substrate. The second PCB has a second substrate and a plurality of conductive traces formed using conductive ink, and the second PCB is flexible. Each of the plurality of temperature sensors is electrically connected to at least one of the conductive traces of the second PCB. The flexible backing is positioned behind the first PCB and the second PCB, configured to support the first PCB and the second PCB, and at least a portion of the flexible backing extends laterally beyond both the first PCB and the second PCB and is covered with a biocompatible adhesive for adhesion to the skin. The first PCB has an outer boundary, the second PCB has an outer boundary, and the first PCB and the second PCB are positioned such that a bulge most closely surrounding the outer boundary of the second PCB lies outside the outer boundary of the first PCB.

[0022] Some embodiments of the third device further include: a first conductive adhesive or conductive gel layer disposed on and in front of both the first PCB and the second PCB; an anisotropic material layer disposed on and in front of the first conductive adhesive or conductive gel layer; and a second conductive adhesive or conductive gel layer disposed on and in front of the anisotropic material layer.

[0023] Optionally, in the embodiments described in the preceding paragraph, the anisotropic material layer comprises graphite. Optionally, in the embodiments described in the preceding paragraph, the anisotropic material layer comprises a pyrolytic graphite layer, a graphitized polymer film, or a graphite foil made from compressed, high-purity exfoliated mineral graphite. Optionally, in the embodiments described in the preceding paragraph, the first PCB further comprises at least one dielectric material layer disposed on and in front of the at least one metal pad, and the dielectric constant of the at least one dielectric material layer is at least 10. In some embodiments of the third device, the plurality of temperature sensors comprises at least two temperature sensors, at least three temperature sensors, or at least four temperature sensors. Attached Figure Description

[0024] Figure 1 It is a plan view of a device used to apply an alternating electric field (e.g., TTField) to the body of a subject.

[0025] Figure 2 yes Figure 1 A cross-sectional view of the device.

[0026] Figure 3 Describes how to use Figure 1 An example of a device that applies an alternating electric field (e.g., TTField) to the body of a subject.

[0027] Figure 4 This is a plan view of another device used to apply an alternating electric field (e.g., TTField) to the body of a subject.

[0028] Figure 5 yes Figure 4 A cross-sectional view of the device.

[0029] Figure 6 Another device for applying an alternating electric field (e.g., TTField) to the body of a subject is described.

[0030] Figure 7 This is a cross-sectional view depicting yet another device used to apply an alternating electric field (e.g., TTField) to the body of a subject.

[0031] Figure 8 An apparatus for applying an alternating electric field (e.g., TTField) to a subject's body using two overlapping PCBs is described.

[0032] Figure 9 Another device for applying an alternating electric field (e.g., TTField) to a subject's body using two overlapping PCBs is described.

[0033] Various embodiments are described in detail below with reference to the accompanying drawings, wherein the same reference numerals denote the same elements. Detailed Implementation

[0034] It is worth noting that in the two prior art designs described above, the hottest point is always located directly beneath one of the electrode elements. Therefore, it is reasonable for these prior art systems to rely on temperature readings obtained at the electrode elements. However, for other designs of transducer arrays, obtaining temperature measurements only at the locations of the electrode elements may be insufficient to ensure that no part of the transducer array heats up beyond a safe threshold. This is particularly important in designs that use sheets of thermally conductive material (e.g., graphite) to transfer heat within any given transducer array. An example of this type of transducer array is described in U.S. Publication No. 2023 / 0043071, the entire contents of which are incorporated herein by reference.

[0035] picture Figure 1 This is a plan view of a device 100 (e.g., a transducer array) for applying an alternating electric field (e.g., a TTField) to the body of a subject, and Figure 2 This is a cross-sectional view of the same device 100. Device 100 includes at least one metal pad 12 positioned at the center portion of the device, and a set of temperature sensors (e.g., thermistors) T1-T8 positioned at the periphery of the device for obtaining temperature readings of the periphery of the device.

[0036] Device 100 uses a flexible PCB 10 having a central segment 10C and peripheral segments (i.e., segments located outside the outer boundary of the central segment 10C). Note that, as used herein, the term "PCB" refers to a printed circuit board, and this term includes rigid PCBs (e.g., those with copper traces on a rigid epoxy board), flexible circuits (e.g., those with copper traces on a flexible polyimide substrate), and printed circuits manufactured by printing conductive ink onto a flexible substrate.

[0037] PCB 10 has at least one metal pad 12 disposed on the front side of the central section 10C of the PCB, and multiple conductive traces (not shown). At least two temperature sensors T1-T8 (e.g., thermistors) are mounted to the peripheral section of PCB 10 (e.g., four or more temperature sensors for electrode elements / metal pads distributed in a square or rectangular pattern), and these temperature sensors are electrically connected to at least one of the conductive traces. Optionally, one or more additional temperature sensors (e.g., thermistors) T9 may be positioned in the central section of device 100. Connector 15 is mounted to PCB 10, and connector 15 is used to provide an electrical interface with the thermistors T1-T9 and at least one metal pad 12. When more than one metal pad 12 is included (e.g. Figures 1 to 2 As depicted, all metal pads 12 can be connected via conductive traces (e.g., metal traces) 13, in which case only a single pin of connector 15 is needed to apply an AC signal to all metal pads 12. In an alternative embodiment (not shown), conductive traces 13 may be omitted, and each metal pad 12 may be electrically connected to its individual pin on connector 15.

[0038] exist Figures 1 to 2 In the depicted embodiment, the PCB 10 further includes a dielectric material layer 18 disposed on and in front of the metal pad 12, and the dielectric material layer 18 (in) Figure 2 The dielectric constant of the dielectric material layer 18 (labeled "hi-K") is at least 10. In some preferred embodiments, the dielectric constant of the dielectric material layer 18 is at least 20 or at least 40. A first conductive adhesive layer 50 may be disposed on and on the front of the PCB 10. Figures 1 to 2 In this embodiment, a first conductive adhesive layer 50 is shown disposed on and on the front of the PCB 10, with the rear surface of the conductive adhesive 50 attached to the front surface of the dielectric material 18 and the front surface of the thermistors T1-T8 (and T9, if present). Note that in some embodiments, the dielectric material layer 18 is not included, in which case the rear surface of the first conductive adhesive layer 50 will be attached to the front surface of the metal pad 12 and the front surface of the thermistors T1-T8 (and T9, if present). Note that in alternative embodiments, a conductive gel layer (e.g., hydrogel) may be used instead. Figure 2 The first conductive adhesive layer 50 is depicted.

[0039] A flexible backing 80 (e.g., a bandage-like backing) is positioned behind the PCB 10 and is configured to support the PCB. At least a portion of the flexible backing 80 extends laterally beyond the PCB, and the front of this portion is covered with a biocompatible adhesive that adheres to the skin. This portion of the flexible backing 80 helps to hold the device 100 against the subject's skin.

[0040] Figures 1 to 2 The depicted embodiment further includes: an anisotropic material layer (e.g., a graphite sheet) 55 disposed on and in front of the first conductive adhesive layer 50; and a second conductive adhesive layer 60 disposed on and in front of the anisotropic material layer 55. The anisotropic material layer 55 may be a pyrolytic graphite layer, a graphitized polymer film, or a graphite foil made from compressed, high-purity exfoliated mineral graphite. The area of ​​the anisotropic material layer 55 is larger than the area of ​​the central section 10C (e.g., at least twice as large). The anisotropic material layer 55 preferably has both thermal and electrical conductivity, and its function is to direct the flow of current and heat in all four directions (i.e., to the right, to the left, and into the center). Figure 2 The page and leaving the page correspond to Figure 1 The device spreads (to the right, left, top, and bottom). The second conductive adhesive layer 60 should be biocompatible and its function is to hold the device 100 against the subject's skin. Note that in an alternative embodiment, a conductive gel layer (e.g., hydrogel) may be used instead. Figure 2 The second conductive adhesive layer 60 is depicted.

[0041] In an alternative embodiment, the anisotropic material layer 55 and the second conductive adhesive layer 60 may be omitted. In this case, the first conductive adhesive layer 50 should be biocompatible so that it can be directly attached to the subject's skin.

[0042] In embodiments including the anisotropic material layer 55, positioning the temperature sensors T1-T8 in the peripheral segments of the device 100 is particularly advantageous because, unlike prior art embodiments (where the hottest spot is almost certainly located directly below the electrode elements), embodiments including the anisotropic material layer 55 allow current and heat to propagate over a larger surface area. Therefore, additional factors (including, but not limited to, geometric and anatomical factors) may influence which portion of the device 100 will be the hottest. In one example, geometry has an effect because the parts of opposing transducer arrays closest to each other will operate hotter than the parts further apart in opposing transducer arrays. In another example, anatomical factors have an effect because the segment of the device 100 covering the subject's skin with lower blood flow will be hotter than the segment covering the subject's skin with higher blood flow (because blood flow carries heat away from the device 100). Optionally, one or more additional temperature sensors T9 may be positioned at the central segment 10C of the device 100.

[0043] Figure 3 Describes how to use Figures 1 to 2 The depicted device 100 is an example of applying an alternating electric field (e.g., TTField) to a target area on a subject's body. Reference Figures 1 to 3 The first device 100 is attached to one side of the target area on the subject's skin, and the second device 100 is attached to the other side of the target area on the subject's skin. To apply an alternating electric field to the target area, an AC voltage generator 120 is mounted on the metal pad 12 of the first device 100. Figures 1 to 2An AC voltage (e.g., between 50 kHz and 5 MHz, or 75 kHz to 300 kHz) is applied between the first device and the metal pad 12 in the second device 100. The AC signal from the AC voltage generator reaches each of the first and second devices 100 via a set of cables terminated at connector 15 in each device 100. Furthermore, from connector 15, the signal is routed to the corresponding metal pad 12 via a corresponding conductive trace (e.g., a conductive metal trace, not shown) on the PCB 10.

[0044] The controller 130 determines the temperature of each of the temperature sensors T1-T8 (and T9, if present) in each of the first and second devices 100 by receiving corresponding signals from these temperature sensors. These signals reach the controller 130 via corresponding conductive traces on the respective PCB 10, corresponding connectors 15, and corresponding cables. If the controller 130 determines that all temperature sensors are below a threshold temperature, the controller 130 may increase the voltage of the AC signal, thereby increasing the current flowing through the first and second devices 100, which in turn increases the intensity of the alternating electric field in the target area. On the other hand, if the controller 130 determines that any of these temperature sensors is at or near a threshold temperature, the controller 130 will decrease the voltage of the AC signal, which will decrease the current and ultimately reduce the temperature of the hottest area of ​​the device 100.

[0045] It is worth noting that the signal sent by the AC voltage generator 120 to the metal pad 12 of the first and second devices 100 has a high current (e.g., approximately 1A or higher). On the other hand, the signal used by the controller 130 to determine the temperature of each of the temperature sensors T1-T8 (and T9, if present) is on the order of lower magnitude (e.g., approximately 1mA or even lower). Therefore, the signal can be routed from connector 15 to the metal pad 12 using a thicker metal trace (e.g., copper trace) and from connector 15 to temperature sensors T1-T8 (and T9, if present) using a thinner metal trace (e.g., copper trace), thus implementing PCB 10. While this is not a problem from a technical point of view, it is suboptimal from an economic point of view.

[0046] More specifically, because the transducer array has a relatively large area (e.g., approximately 10 to 50 square inches), a single PCB 10 will be relatively expensive when used for both routing signals to the metal pad 12 (for applying the TTField) and routing signals from temperature sensors T1-T8 (and T9, if present) for acquiring temperature readings. This is because when using a single PCB 10, the entire PCB must be designed to accommodate the maximum desired current, even though only a small portion of the PCB is actually used to carry the higher current. Large PCBs capable of accommodating currents on the order of approximately 1A are relatively expensive. The following section combines... Figures 4 to 7 The described embodiments solve this economic problem.

[0047] Figure 4 It is a plan view of another device 200 (e.g., a transducer array) for applying an alternating electric field (e.g., a TTField) to the body of a subject, and Figure 5 This is a cross-sectional view of the same device 200. Device 200 includes a first PCB 30 located at the central portion of the device and a second PCB 40 located at the peripheral portion of the device. The first PCB 30 has an outer boundary (as shown by the -.- line), and the first and second PCBs are positioned such that the second PCB 40 is located outside the outer boundary of the first PCB 30.

[0048] The first PCB 30 in the central portion has a first substrate and at least one metal pad 12 disposed on the front side of the first substrate. When more than one metal pad 12 is included (e.g. Figures 4 to 5 As depicted, all metal pads 12 can be connected via conductive traces (e.g., metal traces) 13. Conductive metal traces (e.g., copper traces, not shown) on the first PCB 30 are used to route signals arriving from the AC voltage generator to the metal pads 12. Connectors (not shown) may be included on the first PCB 30 for inputting these signals, or the signals may be directly electrically connected to one of the metal pads 12 or the metal traces 13 using hardwiring connections.

[0049] The second PCB 40 in the peripheral portion of the device 200 (having an outer boundary 40A and an inner boundary 40B, each in Figure 4 The device 200 (shown as dashed lines) is flexible and has a second substrate on which multiple conductive traces are disposed. At least two temperature sensors T1-T8 (e.g., thermistors) are mounted on the second PCB 40, and these temperature sensors are electrically connected to at least one of the conductive traces. Optionally, one or more additional temperature sensors T9 (e.g., thermistors) may be positioned in the central portion of the device 200 (e.g., on the second PCB 40, such as...). Figure 4(As depicted). Connector 45 is mounted on the second PCB 40, and connector 45 is used to provide an electrical interface with thermistors T1 to T9.

[0050] exist Figures 4 to 5 In the depicted embodiment, the first PCB 30 further includes a dielectric material layer 18 disposed on and in front of the metal pad 12, and the dielectric material layer 18 (in) Figure 5 The dielectric constant of the dielectric material layer 18 (marked as "hi-K") is at least 10. In some preferred embodiments, the dielectric constant of the dielectric material layer 18 is at least 20 or at least 40.

[0051] A first conductive adhesive layer 50 is disposed on both the first PCB 30 and the second PCB 40 and on their front surfaces, and the rear surface of the conductive adhesive 50 is attached to the front surface of the dielectric material 18 (of the first PCB 30). In some embodiments, the dielectric material layer 18 is not included (e.g., hereinafter referred to as...). Figure 7 (As described). Note that in alternative embodiments, a conductive gel layer (e.g., hydrogel) may be used instead. Figure 5 The first conductive adhesive layer 50 is depicted in the figure.

[0052] A flexible backing 80 (e.g., a bandage-like backing) is positioned behind both the first PCB 30 and the second PCB 40, and the flexible backing 80 is configured to support both PCBs. At least a portion of the flexible backing 80 extends laterally beyond the first PCB 30 and the second PCB 40, and the front of this portion is covered with a skin-adhesive biocompatible adhesive. This portion of the flexible backing 80 helps to hold the device 200 against the subject's skin. Although for simplicity, the boundaries of the flexible backing 80 and the first PCB 30 and the second PCB 40 are generally depicted as squares or rectangles herein, they can of course be any shape, including circles, ellipses, rounded triangles, etc.

[0053] Figures 4 to 5 The depicted embodiment further includes: an anisotropic material layer (e.g., graphite sheet) 55 disposed on and in front of the first conductive adhesive layer 50; and a second conductive adhesive layer 60 disposed on and in front of the anisotropic material layer 55. The area of ​​the anisotropic material layer 55 is larger than the area of ​​the first PCB 30 (e.g., at least twice the size). The anisotropic material layer 55 preferably has both thermal and electrical conductivity, and its function is to direct the flow of current and heat along the bonding... Figures 1 to 2 Propagation occurs in all four described directions. The second conductive adhesive layer 60 should be biocompatible and function to hold the device 200 against the subject's skin. Note that in an alternative embodiment, a conductive gel layer (e.g., hydrogel) may be used instead. Figure 5 The second conductive adhesive layer 60 is depicted.

[0054] In an alternative embodiment, the anisotropic material layer 55 and the second conductive adhesive layer 60 may be omitted. In this case, the first conductive adhesive layer 50 should be biocompatible so that it can be directly attached to the subject's skin.

[0055] Due to the above combination Figures 1 to 2 For the same reasons described in the embodiments, it is advantageous to position the temperature sensors T1-T8 in the peripheral section of the device 200.

[0056] It is worth noting that, in Figures 1 to 2 In this embodiment, low-current PCB traces (for interfacing with temperature sensors T1-T9) and high-current traces (for interfacing with metal pad 12) are implemented on the same PCB. Unlike this embodiment, all traces on the second PCB 40 are low-current traces. This allows the second PCB 40 to be manufactured using very inexpensive techniques (e.g., using conductive traces made of conductive ink instead of copper). Furthermore, since all the high-current traces are located on the relatively small first PCB 30, therefore... Figures 4 to 5 The embodiments can be implemented using relatively small high-current PCBs (using expensive copper technology) and relatively large low-current PCBs (using cheaper technologies such as conductive ink). Furthermore, due to... Figures 4 to 5 The size ratio of the expensive technology PCB 30 in the embodiment Figures 1 to 2 In the embodiment, the single large-size, expensive technology PCB 10 is much smaller, so the former can save a lot of costs compared to the latter.

[0057] Figures 4 to 5 The described method of using device 200 is similar to that of device 100 (e.g.) Figures 1 to 2 The usage of (as described above) is similar, as in the above context. Figure 3 As described, but with one notable exception. More specifically, Figures 4 to 5 The embodiment does not use a single connector 15 to connect the thermistors T1-T8 (and T9, if present) and the metal pad 12 (as in...). Figures 1 to 2 In this embodiment, instead of routing signals from either source, the signals are routed to thermistors T1-T8 (and optionally T9) using only connector 45 on the second PCB 40. Additionally, the AC TTField signal is routed to metal pad 12 using an additional connector (not shown) or hardwired connection.

[0058] Figure 6 Describes the combination with the above text Figures 4 to 5The described device 200 is similar to another device 200', but there is a larger space between the outer boundary of the first PCB 30 (as shown by the -.- line) and the inner boundary 40B of the second PCB 40 (as shown by the dashed line). The use of this device 200' (and...) Figure 6 The labeling of component 200' in the above description is related to the use of device 200. Figures 4 to 5 Similar to the tag of the 200 component in the text.

[0059] Figure 7 Depicting the same combination with the above text Figures 4 to 5 The described device 200 is another device 200 similar to the one described above, but the dielectric material layer 18 is omitted. Therefore, the rear surface of the first conductive adhesive layer 50 will adhere to the front surface of the metal pad 12 of the first PCB 30. When it is expected that the voltage from the AC voltage generator 120 (such as...) will be applied... Figure 3 When the AC signal (as shown) is electrically coupled to the subject's body (instead of capacitively coupling the signal to the subject's body), the device 200” is used instead of the device 200 described above.

[0060] In conjunction with the above Figure 4 and Figure 6 In the described embodiment, a space exists between the outer boundary of the first PCB 30 (as shown by the -.- line) and the inner boundary 40B of the second PCB 40 (as shown by the dashed line). This space is... Figure 4 It is very small in the middle, but Figure 6 It is very large, and Figure 4 or Figure 6 In none of the embodiments, the second PCB 40 is shown to overlap with the first PCB 30. However, in an alternative embodiment, the second PCB 40 may partially or completely overlap with the first PCB 30. Figure 8 This is an example of such embodiment 300. Figure 8 Examples and Figure 4 Example 200 is similar, but the second PCB 40 (shown with a slanted line) is a rectangle without any cut-out areas. Preferably, at the point where the first PCB 30 and the second PCB 40 overlap, the second PCB 40 is positioned behind the first PCB 30 (i.e., the first PCB 30 is in front, and the second PCB 40 is behind). In this example, the first PCB 30 has an outer boundary (as shown by the -.- line), the second PCB 40 has an outer boundary 40A (as shown by the dashed line), and the first PCB 30 and the second PCB 40 are positioned such that the outer boundary of the second PCB 40 lies outside the outer boundary of the first PCB 30 (when viewed from a direction perpendicular to the first PCB 30). Figure 8In this configuration, the second PCB 40 completely overlaps with the first PCB 30. Optionally, in embodiments where the second PCB 40 partially or completely overlaps with the first PCB 30, the first PCB 30 and the second PCB 40 may be laminated together. Optionally, the laminate may include a conductive adhesive between the first PCB 30 and the second PCB 40.

[0061] Figure 9 for Figure 8 A variation of the embodiment in which the second PCB 40 has an irregular shape. In this case, the first PCB 30 has an outer boundary (as shown by the -.- line), the second PCB 40 has an outer boundary 40A (as shown by the dashed line), and the first PCB 30 and the second PCB 40 are positioned such that the rectangle that most closely surrounds the outer boundary of the second PCB 40 lies outside the outer boundary of the first PCB 30 (although a portion of the first PCB 30 actually lies outside the outer boundary of the second PCB 40).

[0062] The headings are provided for convenience only and should not be construed as limiting this disclosure in any way. Embodiments illustrated under any heading or in any part of this disclosure may be combined with embodiments illustrated under the same or any other heading or other part of this disclosure. Unless otherwise stated herein or clearly contradicted by the context, this disclosure covers any combination of the elements described herein in all possible variations. For example, but not limited to, embodiments described with respect to a given embodiment in the format of dependent claims (e.g., a given embodiment described in the format of independent claims) may be combined with other embodiments (described in the format of independent claims or dependent claims).

[0063] While the invention has been disclosed with reference to certain embodiments, various modifications, alterations, and changes can be made to the described embodiments without departing from the scope and domain of the invention as defined by the appended claims. Therefore, the invention is intended to be limited to the described embodiments, but rather to have the full scope defined by the language of the appended claims and their equivalents.

Claims

1. A device for applying an electrical signal to the body of a subject, the device comprising: A first PCB, the first PCB having a first substrate and at least one metal pad disposed on the skin-facing side of the first substrate; A second PCB having a second substrate and multiple conductive traces, wherein the second PCB is flexible; and Multiple temperature sensors, each of which is electrically connected to at least one conductive trace on the second PCB. The first PCB has an outer boundary, and the first PCB and the second PCB are positioned such that when viewed from a direction perpendicular to the first PCB, the second PCB is located outside the outer boundary of the first PCB.

2. The apparatus of claim 1, further comprising a flexible backing positioned behind the first PCB and the second PCB, wherein the flexible backing is configured to support the first PCB and the second PCB, and wherein at least a portion of the flexible backing extends laterally beyond both the first PCB and the second PCB and is covered with a skin-adhesive biocompatible adhesive. The first PCB is flexible, and The multiple conductive traces on the second PCB are formed using conductive ink.

3. The apparatus of claim 2, wherein the first PCB has a first area, the second PCB has a second area, and the second area is larger than the first area.

4. The apparatus according to claim 2, further comprising: A first conductive adhesive or conductive gel layer is disposed on and in front of both the first PCB and the second PCB; An anisotropic material layer is disposed on and in front of the first conductive adhesive or conductive gel; and A second conductive adhesive or conductive gel layer is disposed on and in front of the anisotropic material layer.

5. The apparatus of claim 4, wherein the anisotropic material layer comprises graphite.

6. The apparatus of claim 4, wherein the anisotropic material layer comprises a pyrolytic graphite layer, a graphitized polymer film, or a graphite foil made of compressed high-purity exfoliated mineral graphite.

7. The apparatus of claim 1, wherein each of the metal pads is a copper pad.

8. The apparatus of claim 1, further comprising at least one dielectric material layer disposed in front of the at least one metal pad, optionally disposed on and in front of the at least one metal pad, wherein the dielectric constant of the at least one dielectric material layer is at least 10.

9. The apparatus of claim 1, further comprising a connector fixed to the second PCB, wherein the plurality of temperature sensors, the plurality of conductive traces of the second PCB, and the connector are positioned and arranged such that temperature readings obtained using the plurality of temperature sensors can be accessed via the connector.

10. The apparatus of claim 1, wherein the first substrate and the second substrate partially or completely overlap each other in the overlap region and are laminated together in the overlap region.

11. The apparatus of claim 1, wherein the first substrate and the second substrate are the same substrate, or wherein the first substrate and the second substrate are coplanar.

12. A device for applying an electrical signal to the body of a subject, the device comprising: A flexible PCB having a central section and a peripheral section located outside the outer boundary of the central section, wherein the PCB has at least one metal pad disposed on the skin-facing side of the central section of the PCB, and multiple conductive traces. At least two temperature sensors, each of the temperature sensors being mounted to the peripheral segment of the PCB and electrically connected to at least one of the conductive traces; A first conductive adhesive or conductive gel layer is disposed on and on the front of the PCB. and A flexible backing positioned behind the PCB, wherein the flexible backing is configured to support the PCB, and wherein at least a portion of the flexible backing extends laterally beyond the PCB and is covered with a biocompatible adhesive for skin adhesion.

13. The apparatus of claim 12, wherein the central segment of the flexible PCB is defined by a bulge that surrounds the perimeter of the outermost metal pad of the at least one metal pad.

14. The apparatus of claim 12, further comprising: An anisotropic material layer is disposed on and in front of the first conductive adhesive or conductive gel layer, wherein the area of ​​the anisotropic material layer is at least twice the area of ​​the central segment. and A second conductive adhesive or conductive gel layer is disposed on and in front of the anisotropic material layer.

15. The apparatus of claim 14, wherein the anisotropic material layer comprises graphite.

16. The apparatus of claim 12, wherein the PCB further comprises at least one dielectric material layer disposed on and in front of the at least one metal pad, wherein the dielectric constant of the at least one dielectric material layer is at least 10.

17. The apparatus of claim 12, wherein none of the at least one metal pad is located in the peripheral section of the PCB.

18. An apparatus for applying an electrical signal to the body of a subject, the apparatus comprising: A first PCB, the first PCB having a first substrate and at least one metal pad disposed on the skin-facing side of the first substrate; The second PCB has a second substrate and multiple conductive traces formed using conductive ink, wherein the second PCB is flexible; Multiple temperature sensors, each of which is electrically connected to at least one of the conductive traces on the second PCB; and A flexible backing is positioned behind the first PCB and the second PCB, wherein the flexible backing is configured to support the first PCB and the second PCB, and wherein at least a portion of the flexible backing extends laterally beyond both the first PCB and the second PCB and is covered with a skin-adhesive biocompatible adhesive. The first PCB has an outer boundary, the second PCB has an outer boundary, and the first PCB and the second PCB are positioned such that the convex hull of the outer boundary of the second PCB that most closely surrounds the second PCB is located outside the outer boundary of the first PCB.

19. The apparatus of claim 18, further comprising: A first conductive adhesive or conductive gel layer is disposed on and in front of both the first PCB and the second PCB; An anisotropic material layer is disposed on and in front of the first conductive adhesive or conductive gel; and A second conductive adhesive or conductive gel layer is disposed on and in front of the anisotropic material layer.

20. The apparatus of claim 19, wherein the anisotropic material layer comprises graphite.

21. The apparatus of claim 19, wherein the first PCB further comprises at least one dielectric material layer disposed on and in front of the at least one metal pad, wherein the dielectric constant of the at least one dielectric material layer is at least 10.

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