Determination of the Lesion Size in Laser-Induced Interstitial Thermal Therapy (LITT) using a Low-Field MRI

This study aimed to compare MR thermal mapping during laser-induced interstitial thermal therapy (LITT) to thermal lesions observed macroscopically, in order to estimate the 3D size of the coagulative necrosis. Laser irradiation was performed ex-vivo with a 980 nm laser in pig liver in a open low-magnetic field (0.2 T) scanner. The laser light was transmitted through a 1040/600 mum (outer/core diameter) bare-tip silica fiber. The laser energy was applied on a pulsed mode (10 s laser-on, 10 s laser-off) for 12 minutes, power: 6 W, energy: 2160 J. MR thermal mapping used T1 method for its simplicity and its efficiency at low magnetic field.