Image-guided therapy of a tissue can utilize magnetic resonance imaging (MRI) or another medical imaging device to guide an instrument within the tissue. A workstation can actuate movement of the instrument, and can actuate energy emission and/or cooling of the instrument to effect treatment to the tissue. The instrument can be an MRI compatible laser probe that provides thermal therapy to, e.g., a tissue in a brain of a patient. By tracking a probe position within tissue through feedback, multiple data slices provided around the probe position can be processed to monitor treatment and view thermal data. The operator selects treatment area reference points with the assistance of noise masking.