# US 8,718,756 B2 · Optimizing characteristics of an electric field to increase the field's effect on proliferating cells

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- Number: US 8,718,756 B2
- Document ID: US8718756B2
- Status: Granted
- Kind: B2
- Application number: 12/851,761
- Filed: 2010-08-06
- Published: 2010-12-23
- Granted: 2014-05-06
- Earliest claimed: 2005-10-03
- Assignees: Novocure GmbH
- Applicants: Yoram Palti
- Inventors: Yoram Palti
- Web page: https://patentgrep.com/patent/US8718756B2

## CPC

- A61N 1/32: alternating or intermittent currents {(applying electric fields by inductive or capacitive coupling A61N1/40; microwave apparatus A61N5/02)}
- A61N 1/36002: {Cancer treatment, e.g. tumour}
- A61N 1/40: Applying electric fields by inductive or capacitive coupling (microwave apparatus A61N5/00); {Applying radio-frequency signals}
- A61N 1/0476: {Array electrodes (including any electrode arrangement with more than one electrode for at least one of the polarities)}
- A61N 1/36034: {specified by the stimulation parameters}
- A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B)

## Abstract

AC electric fields at particular frequencies and field strengths have been shown to be effective for destroying rapidly proliferating cells such as cancer cells. The effectiveness of such fields is improved when the field is sequentially switched between two or more different directions. The effectiveness of such fields can be improved even further by choosing the rate at which the field is switched between the various directions.

## Claims

### Claim 1

An apparatus for applying a therapeutic electric field to a target region, the apparatus comprising:
a first pair of insulated electrodes, each electrode having a conductor and a surface configured for placement against a patient's body that is insulated from the conductor;
a second pair of insulated electrodes, each electrode having a conductor and a surface configured for placement against a patient's body that is insulated from the conductor;
a signal generator that generates a periodic control signal with first and second output states, the first and second output states each having a duration between 20 and 500 ms;
an AC signal generator that generates a first AC signal across the conductors of the first pair of electrodes when the control signal is in the first output state and generates a second AC signal across the conductors of the second pair of electrodes when the control signal is in the second output state, the first and second AC signals having a frequency between 50 and 500 kHz.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein the duration of the first output state is between 50 and 250 ms, and the duration of the second output state is between 50 and 250 ms.

### Claim 3 (depends on 2)

The apparatus of claim 2, wherein the first and second AC signals having a frequency between 100 and 200 kHz.

### Claim 4 (depends on 1)

The apparatus of claim 1, wherein the AC signal generator comprises a single signal source and a switch that distributes an output of the single signal source to either the first pair of electrodes or the second pair of electrodes.

### Claim 5 (depends on 1)

The apparatus of claim 1, wherein the AC signal generator comprises a first signal source operatively connected to the first pair of electrodes and a second signal source operatively connected to the second pair of electrodes.

### Claim 6 (depends on 1)

The apparatus of claim 1, wherein the first AC signal and the second AC signal are turned on at a rate that is slow relative to the reciprocal of the field frequency, and fast relative to the duration of the first output state.

### Claim 7 (depends on 1)

The apparatus of claim 1, wherein the first AC signal and the second AC signal are turned on at a rate that reaches 90% of the steady-state values between 1-5 ms.

### Claim 8 (depends on 1)

The apparatus of claim 1, wherein the periodic control signal is a square wave.

### Claim 9 (depends on 2)

The apparatus of claim 2, wherein the AC signal generator comprises a single signal source and a switch that distributes an output of the single signal source to either the first pair of electrodes or the second pair of electrodes.

### Claim 10 (depends on 2)

The apparatus of claim 2, wherein the AC signal generator comprises a first signal source operatively connected to the first pair of electrodes and a second signal source operatively connected to the second pair of electrodes.

### Claim 11 (depends on 2)

The apparatus of claim 2, wherein the first AC signal and the second AC signal are turned on at a rate that is slow relative to the reciprocal of the field frequency, and fast relative to the duration of the first output state.

### Claim 12 (depends on 2)

The apparatus of claim 2, wherein the first AC signal and the second AC signal are turned on at a rate that reaches 90% of the steady-state values between 1-5 ms.

### Claim 13 (depends on 2)

The apparatus of claim 2, wherein the periodic control signal is a square wave.