Thermal ablation a comparison of thermal dose required for radiofrequency-, microwave-, and laser-induced coagulation in an ex vivo bovine liver model.

Rationale And Objectives: To compare thermal dosimetry metrics for specified diameters of coagulation achieved using three different ablation energy sources.

Materials And Methods: 204 ablations measuring 20, 30, or 40 +/- 2 mm were created in an ex-vivo bovine liver model using 1) 2.5 cm cluster RF electrodes (n = 114), 2) 3 cm microwave antennas (n = 45), and 3) 3 cm laser diffusing fibers (n = 45).

Radiofrequency ablation: the effect of distance and baseline temperature on thermal dose required for coagulation.

Purpose: To determine the effects of applied current, distance from an RF electrode and baseline tissue temperature upon thermal dosimetry requirements to induce coagulation in ex vivo bovine liver and in vivo porcine muscle models.

Materials And Methods: RF ablation was performed in ex vivo liver at varying baseline temperatures-19-21 degrees C (n = 114), 8-10 degrees C (n = 27), and 27-28 degrees C (n = 27)-using a 3-cm tip electrode and systematically varied current 400-1,300 mA, to achieve defined diameters of coagulation (20, 30 and 40 +/- 2 mm), and in in vivo muscle (n = 18) to achieve 35 mm +/- 2 mm of coagulation. Thermal dose required for coagulation was calculated as the area under the curve and cumulative equivalent minutes at 43 degrees C.

Radiofrequency ablation: variability in heat sensitivity in tumors and tissues.

Purpose: To characterize the thermal dosimetry (ie, heating profile) of radiofrequency ablation (RFA) in multiple ex vivo tissues and in vivo tumor models.

Materials And Methods: RFA was performed for 3-24 minutes in ex vivo bovine livers (n=20), porcine kidneys (n=20), and turkey muscles (n=20) and in vivo canine venereal sarcomas (n=8). RFA was performed by using 1 and 3-cm long tips internally cooled electrodes.