An apparatus for use together with an AC signal generator for imposing electric fields through a target region in a subject's body, the apparatus comprising: a hub configured to accept digital data corresponding to pluralities of temperature readings from a plurality of transducer arrays and output digital data corresponding to each of the pluralities of temperature readings to the AC signal generator, wherein the hub includes a plurality of conductors configured to route current from the AC signal generator to respective positions that are located distally beyond the hub; and a plurality of transducer arrays, each transducer array comprising: a plurality of capacitively-coupled electrode elements configured for placement against the subject's body at one of the respective positions; a substrate configured to hold the plurality of electrode elements against the subject's body at the one of the respective positions; a plurality of temperature sensors positioned to sense temperatures at respective ones of the plurality of electrode elements; an analog multiplexer having an analog output and a plurality of selectable analog inputs, wherein each of the plurality of analog inputs of the analog multiplexer is operatively connected to a respective one of the plurality of temperature sensors; an analog-to-digital converter configured to digitize signals from the analog output of the analog multiplexer; a controller configured to sequentially select each of the plurality of analog inputs of the analog multiplexer, sequentially obtain, from the analog-to-digital converter, a plurality of temperature readings, each of the plurality of temperature readings corresponding to a respective one of the plurality of temperature sensors, and transmit digital data corresponding to the plurality of temperature readings to the hub; and a cable arranged to route current arriving via the respective conductor in the hub to the plurality of electrode elements, and to route the digital data from the controller to the hub. a hub configured to accept digital data corresponding to pluralities of temperature readings from a plurality of transducer arrays and output digital data corresponding to each of the pluralities of temperature readings to the AC signal generator, wherein the hub includes a plurality of conductors configured to route current from the AC signal generator to respective positions that are located distally beyond the hub; and a plurality of transducer arrays, each transducer array comprising: a plurality of capacitively-coupled electrode elements configured for placement against the subject's body at one of the respective positions; a substrate configured to hold the plurality of electrode elements against the subject's body at the one of the respective positions; a plurality of temperature sensors positioned to sense temperatures at respective ones of the plurality of electrode elements; an analog multiplexer having an analog output and a plurality of selectable analog inputs, wherein each of the plurality of analog inputs of the analog multiplexer is operatively connected to a respective one of the plurality of temperature sensors; an analog-to-digital converter configured to digitize signals from the analog output of the analog multiplexer; a controller configured to sequentially select each of the plurality of analog inputs of the analog multiplexer, sequentially obtain, from the analog-to-digital converter, a plurality of temperature readings, each of the plurality of temperature readings corresponding to a respective one of the plurality of temperature sensors, and transmit digital data corresponding to the plurality of temperature readings to the hub; and a cable arranged to route current arriving via the respective conductor in the hub to the plurality of electrode elements, and to route the digital data from the controller to the hub. a plurality of capacitively-coupled electrode elements configured for placement against the subject's body at one of the respective positions; a substrate configured to hold the plurality of electrode elements against the subject's body at the one of the respective positions; a plurality of temperature sensors positioned to sense temperatures at respective ones of the plurality of electrode elements; an analog multiplexer having an analog output and a plurality of selectable analog inputs, wherein each of the plurality of analog inputs of the analog multiplexer is operatively connected to a respective one of the plurality of temperature sensors; an analog-to-digital converter configured to digitize signals from the analog output of the analog multiplexer; a controller configured to sequentially select each of the plurality of analog inputs of the analog multiplexer, sequentially obtain, from the analog-to-digital converter, a plurality of temperature readings, each of the plurality of temperature readings corresponding to a respective one of the plurality of temperature sensors, and transmit digital data corresponding to the plurality of temperature readings to the hub; and a cable arranged to route current arriving via the respective conductor in the hub to the plurality of electrode elements, and to route the digital data from the controller to the hub.