MR thermometry-based feedback control of laser interstitial thermal therapy at 980 nm

The goal of this study was to explore the feasibility of magnetic resonance thermal imaging (MRTI)-based feedback control of intracerebral laser interstitial thermal therapy (LITT), using a computer workstation and 980-nm diode laser interfaced to an MR scanner.

A computer-controlled laser thermal therapy system was used to produce 12 ex vivo lesions in 3 canine and porcine brains and 16 in vivo lesions in 6 canines with diffusing tip fiberoptic applicators and energies from 54 to 900 J. MRTI predictions of thermal damage were correlated with histopathologic analysis.

Under feedback control, no carbonization, vaporization, or applicator damage was observed. MRTI-based prediction of thermal dose was not significantly different from histological evaluation of achieved thermal necrosis.

The computer-controlled thermal therapy system was effective at regulating heating, eliminating carbonization and vaporization, and protecting fiberoptic applicators. MRTI estimation of thermal dose accurately predicted achieved thermal necrosis.