An apparatus for catheterization, comprising: a probe adapted for insertion into contact with a target tissue in a body of a subject, the probe having a longitudinal axis, a plurality of temperature sensors on a distal portion of the probe and an ablation electrode thereon, the temperature sensors being distributed circumferentially about the longitudinal axis on the distal portion; a processor operative for applying energy through the ablation electrode to ablate the target tissue in the body, and while applying energy performing the steps of: repetitively recording data from the temperature sensors; establishing a baseline temperature level from the data; thereafter from the data detecting a drop in temperature with respect to the baseline temperature level; responsively to the drop in temperature, concluding that a loss of contact between the probe and the target tissue has occurred; and alerting an operator to the loss of contact, wherein the plurality of temperature sensors comprises a plurality of arrays of temperature sensors, wherein each array of temperature sensors comprises at least three temperature sensors, wherein each array is circumferentially distributed about the longitudinal axis of the probe at a different axial location; and wherein the apparatus is characterised in that: the plurality of temperature sensors are mounted within ribs integral to the ablation electrode, wherein the ribs are made from the same material as an outer surface of the electrode. a probe adapted for insertion into contact with a target tissue in a body of a subject, the probe having a longitudinal axis, a plurality of temperature sensors on a distal portion of the probe and an ablation electrode thereon, the temperature sensors being distributed circumferentially about the longitudinal axis on the distal portion; a processor operative for applying energy through the ablation electrode to ablate the target tissue in the body, and while applying energy performing the steps of: repetitively recording data from the temperature sensors; establishing a baseline temperature level from the data; thereafter from the data detecting a drop in temperature with respect to the baseline temperature level; responsively to the drop in temperature, concluding that a loss of contact between the probe and the target tissue has occurred; and alerting an operator to the loss of contact, repetitively recording data from the temperature sensors; establishing a baseline temperature level from the data; thereafter from the data detecting a drop in temperature with respect to the baseline temperature level; responsively to the drop in temperature, concluding that a loss of contact between the probe and the target tissue has occurred; and alerting an operator to the loss of contact, wherein the plurality of temperature sensors comprises a plurality of arrays of temperature sensors, wherein each array of temperature sensors comprises at least three temperature sensors, wherein each array is circumferentially distributed about the longitudinal axis of the probe at a different axial location; and wherein the apparatus is characterised in that: the plurality of temperature sensors are mounted within ribs integral to the ablation electrode, wherein the ribs are made from the same material as an outer surface of the electrode. the plurality of temperature sensors are mounted within ribs integral to the ablation electrode, wherein the ribs are made from the same material as an outer surface of the electrode.