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EP-4054701-B1 - ARRAYS FOR DELIVERING TUMOR TREATING FIELDS (TTFIELDS) WITH INDIVIDUALLY ACCESSIBLE ELECTRODE ELEMENTS AND TEMPERATURE SENSORS

EP4054701B1EP 4054701 B1EP4054701 B1EP 4054701B1EP-4054701-B1

Inventors

  • WASSERMAN, YORAM

Dates

Publication Date
20260506
Application Date
20201221

Claims (9)

  1. An apparatus for applying an alternating electric field to a subject's body, the apparatus comprising: a plurality of electrode elements (52; 152); a support (59; 159) configured to hold the electrode elements (52; 152) against the subject's body; a plurality of thermistors (54; 154), each of the thermistors (54; 154) having a first terminal and a second terminal and one thermistor (54; 154) being positioned at each electrode element (52; 152) to sense a temperature at the respective electrode element (52; 152); a connector (57; 157) having a plurality of first pins and a second pin; a plurality of first conductors, each of the first conductors providing an electrically-conductive path between a respective one of the first pins, a respective one of the electrode elements (52; 152) and the first terminal of the respective thermistor (54; 154); and a second conductor that provides an electrically-conductive path between the second pin and the second terminal of at least one of the thermistors (54; 154).
  2. The apparatus of claim 1, wherein the second terminals of all of the thermistors (54) are wired together.
  3. The apparatus of claim 2, wherein the second terminals of all of the thermistors (54) are wired together using at least one of at least one trace on a flex circuit and at least one wire.
  4. The apparatus of claim 1, wherein the second terminals of all of the thermistors (54) are wired together, and the second conductor provides an electrically-conductive path between the second pin and the second terminal of all of the thermistors (54).
  5. The apparatus of claim 1, wherein the thermistors (154) are arranged in series, beginning with a first one of the thermistors (154) and ending with a last one of the thermistors (154), the second terminal of each of the thermistors (154) except for the last thermistor (154) is wired to the first terminal of a respective subsequent thermistor (154), and the second conductor provides an electrically-conductive path between the second pin of the connector (157) and the second terminal of the last thermistor (154).
  6. The apparatus of claim 1, wherein the second conductor provides an electrically-conductive path between the second pin and the second terminal of only a single one of the thermistors (154).
  7. The apparatus of claim 1, wherein the plurality of electrode elements comprises at least four electrode elements (52; 152); and wherein the plurality of thermistors comprises at least four thermistors (54; 154).
  8. The apparatus of claim 1, wherein the plurality of electrode elements comprises at least nine electrode elements (52; 152); and wherein the plurality of thermistors comprises at least nine thermistors (54; 154).
  9. The apparatus of claim 1, wherein each of the electrode elements (52; 152) comprises a conductive plate and a dielectric layer disposed on the conductive plate, and the support (59; 159) is configured to hold the electrode elements (52; 152) against the subject's body so that the dielectric layer of each of the electrode elements (52; 152) faces the subject's body.

Description

BACKGROUND TTFields therapy is a proven approach for treating tumors. FIG. 1 is a schematic representation of the prior art Optune® system for delivering TTFields. The TTFields are delivered to patients via four transducer arrays 21-24 that are placed on the patient's skin in close proximity to a tumor (e.g., as depicted in FIGS. 2A-2D for a person with glioblastoma). The transducer arrays 21-24 are arranged in two pairs, and each transducer array is connected via a multi-wire cable to an AC signal generator 20. The AC signal generator (a) sends an AC current through one pair of arrays 21, 22 during a first period of time, which induces an electric field with a first direction through the tumor; then (b) sends an AC current through the other pair of arrays 23, 24 during a second period of time, which induces an electric field with a second direction through the tumor; then repeats steps (a) and (b) for the duration of the treatment. Each transducer array 21-24 is configured as a set of capacitively coupled electrode elements E (e.g., a set of 9 electrode elements, each of which is about 2 cm in diameter) that are interconnected via a flex circuit. Each electrode element includes an electrically conductive substrate with a dielectric layer (more specifically, a layer of ceramic material with a high dielectric constant) disposed thereon. Each electrode element is sandwiched between a layer of an electrically conductive medical gel and an adhesive tape. When placing the arrays on the patient, the medical gel conforms to the contours of the patient's skin and ensures good electric contact of the device with the body. The adhesive tape holds the entire array in place on the patient as the patient goes about their daily activities. The amplitude of the alternating current that is delivered via the transducer arrays is controlled so that skin temperature (as measured on the skin below the transducer arrays) does not exceed a safety threshold of 41° C. The temperature measurements on the patient's skin are obtained using thermistors T placed beneath some of the disks of the transducer arrays. In the existing Optune® system, each array includes 8 thermistors, with one thermistor positioned beneath a respective disk in the array. (Note that most arrays include more than 8 disks, in which case the temperature measurements are only performed beneath a sub-set of the disks within the array). The AC signal generator 20 obtains temperature measurements from all 32 thermistors (4 arrays × 8 thermistors per array), and the controller in the AC signal generator uses the temperature measurements to control the current to be delivered via each pair of arrays in order to maintain temperatures below 41° C on the patient's skin. The current itself is delivered to each array via an additional wire (i.e., one wire 28 for each of the arrays 21-24) that runs from the AC signal generator 20 to each array. And an additional wire (not shown) for each of the arrays 21-24 is used as a common return for all 8 thermistors. Thus, each of the four cables that terminate on the arrays 21-24 in the existing Optune system has a total of 10 conductors Document US-A-2015/112328 discloses an apparatus for applying an alternating electric field to a subject's body. SUMMARY OF THE INVENTION The invention is directed to an apparatus for applying an alternating electric field to a subject's body according to claim 1. Embodiments of the invention are disclosed in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic representation of the prior art Optune® system for delivering TTFields.FIGS. 2A-2D depict the positioning of transducer arrays on a person's head for treating a brain tumor.FIG. 3 depicts a first embodiment of a transducer array that provides an individual conductor for each individual electrode element.FIG. 4 is a block diagram of a system that uses four copies of the FIG. 3 transducer array to apply TTFields to a subject.FIG. 5 depicts a second embodiment of a transducer array that provides an individual conductor for each individual electrode element.FIG. 6 is a block diagram of a system that uses four copies of the FIG. 5 transducer array to apply TTFields to a subject.FIG. 7 is a schematic diagram of a circuit that is suitable for implementing each of the switches in banks 1L and 1R in the FIG. 4 and FIG. 6 embodiments. Various embodiments are described in detail below with reference to the accompanying drawings, wherein like reference numerals represent like elements. DESCRIPTION OF THE PREFERRED EMBODIMENTS Although the FIG. 1 approach described above is very effective for delivering TTFields to a tumor, the effectiveness of the treatment will drop if good electrical contact is not maintained between each of the elements in the four transducer arrays 21-24 and the person's body. This can happen, for example, if the hydrogel beneath one or more elements of the transducer arrays dries out over time, or due to hair