A method of directing energy to tissue includes the initial steps of determining target tissue location and/or target tissue margins, positioning an ablation device for delivery of energy to target tissue, and positioning one or more heat-sensitive optical probes into a tissue region to be monitored. Each heat-sensitive optical probe is adapted to utilize spectral properties of light to access one or more optical fiber portions of the heat-sensitive optical probe in response to heat. The method also includes the steps of applying energy to the ablation device, continuing ablation while size and/or position of ablated zone which received heat above a threshold value is displayed on a monitor using one or more electrical signals generated by the one or more heat-sensitive optical probes, determining whether the ablated zone displayed on the monitor is larger than the target tissue margins, and terminating ablation if it is determined that the ablated zone displayed on the monitor is larger than the target tissue margins.
