This novel technique has recently been shown to be effective in the management of selected brain tumors and as a method for the management of intractable epilepsy. The procedure involves the placement of a 1.65 mm diameter laser catheter through a small opening in the skull (bur hole). The laser catheter is then placed in a precise location in within the brain (target) utilizing frameless stereotactic techniques or with live intra-operative MR localization. Activation of the laser causes intra-tumoral temperatures to rise resulting an in a time-dependent thermal injury to tumor or epileptogenic tissue. The treatment is delivered in an MR imaging suite enabling NJBS surgeons to monitor the anatomical extent and degree of temperature modulation in real time.