Abstract: Devices and systems used to ablate tissue of a tumor using laser energy are disclosed. The devices and systems include a laser probe and a magnetic resonance (MR) safe temperature probe. The MR safe temperature probe includes an optical sensor. A bone anchor fixture separates the laser probe and the MR safe temperature probe to prevent interference in the MR safe temperature probe data. Proton Resonance Frequency (PRF) thermometry is used to model a temperature of a pixel of an MR image located adjacent the optical sensor. The modeled pixel temperature and the measured temperature are compared and monitored. Exceeding a threshold difference value causes an intervening action to occur.