Abstract: Tumor treating fields (TTFields) can be delivered to a subject's body with improved safety and efficacy by determining the condition of participating electrode elements and/or the subject's skin condition under positioned electrode elements. This may be accomplished by applying an AC signal to pairs or groups of electrode elements and taking corresponding impedance measurements. In some embodiments, the impedance measurements are indicative of electrode element condition and/or skin condition. These determined conditions can be used to adjust or pause TTFields treatment, for example to permit skin recovery or to ensure that participating electrode elements will properly function.

Abstract: Tumor treating fields (TTFields) can be delivered to a subject's body at higher field strengths by switching off one or more electrode elements that are overheating without switching off other electrode elements that are not overheating. This may be accomplished using a plurality of temperature sensors, with each of the temperature sensors positioned to sense the temperature at a respective electrode element; and a plurality of electrically controlled switches, each of which is wired to switch the current to an individual electrode element on or off. A controller input signals from the temperature sensors to determine the temperature at each of the electrode elements, and controls the state of the control input of each of the electrically controlled switches to selectively switch off the current or adjusted the duty cycle at any electrode element that is overheating.

Abstract: An apparatus for generating a sinusoid at a pre-set frequency f includes a DC power source with a controllable output voltage, a transformer, a power switch, a sequencer, and an output filter. The power switch is configured to apply the output of the DC power source to the primary of the transformer in either direction or to remain off based on control signals that are applied to its control input. The sequencer applies control signals to the control input in a choreographed sequence to form an oversampled version of a sine wave. The output filter is connected to the secondary of the transformer, and it passes the pre-set frequency f and attenuates frequencies above a cut-off frequency. In some preferred embodiments, the cut-off frequency is 3f and the transfer function of the output filter has a zero at 5f.

Abstract: An apparatus for generating a sinusoid at a pre-set frequency f includes a DC power source with a controllable output voltage, a transformer, a power switch, a sequencer, and an output filter. The power switch is configured to apply the output of the DC power source to the primary of the transformer in either direction or to remain off based on control signals that are applied to its control input. The sequencer applies control signals to the control input in a choreographed sequence to form an oversampled version of a sine wave. The output filter is connected to the secondary of the transformer, and it passes the pre-set frequency f and attenuates frequencies above a cut-off frequency. In some preferred embodiments, the cut-off frequency is 3f and the transfer function of the output filter has a zero at 5f.