The Experimental Study Of Microwave Ablation On Fresh Ex-vivo Porcine Liver With2450MHz Dual-source Cooled-shaft Antenna

OBJECTIVE1. To explore the relationship of ablative shape with the combination of two ablationantenna, power and ablation time, when using2450MHz dual-source cooled-shaft antennaablation on porcine liver when implanted at the same depth.2. To find the combination of the minimum power with the shortest time,whenforming the best solidified form, scope (ie, the largest ellipsoid, and the center does notappear hollow) with two antennas at the same depth and spacing, thus providing aneffective method for completely covering larger tumors.MATERIALS AND METHODSUse2450MHz dual-source cooled-shaft microwave antenna to ablate fresh ex-vivoporcine liver, the experiments performed on30livers and opted to avoid the large bloodvessels, thicker than4cm of fresh liver tissue. successively fixed the two microwaveantennas spacing is2.5cm,3.0cm, and implanted depth is5.0cm,and set microwaveablation power was successively50W,60W,70W, ablation time was successively2min,4min,6min,8min,10min,12min, forming the time/power/spacing unit add up to36exper-imental units, each unit of the experiment was repeated three times. Last observe themorphology of all solidified lesions; measure the longitudinal diameter(LD), transversediameter(TD)and calculate TD/LD and Volume of all ablations. Analyze the regular patter-n of all the ablation data with power, time and spacing. Explore the combination of theminimum power with the shortest time, when forming the largest solidified form with twoantennas at the same implanted depth and spacing.RESULTS1. All coagulation ablation lesions were mostly ellipsoidal or spherical, and with aclear demarcation between the surrounding normal tissue. Cut all the lesions from the inside out, you can see a clear demarcation of four areas: the needle tract carbonation zone,coagulation ablation zone, transition zone and normal liver tissue area. All the ablations’smacroscopic observation result and the corresponding histopathological performance has agood correspondence.2. The form of dual-source microwave ablation lesions have relationship with ablationpower, time, and the antenna spacing. At the same antenna spacing and the same power,set ablation time were successively2min,4min,6min,8min,10min,12min, the solidifiedform of the ablation lesions were related with the ablation time (P<0.0001).With theextension of the ablation time, the blank area between two elliptical spheres (ie, normalliver tissue which ablation zone was not involved in) were getting smaller and smaller,gradually formed the transition zone, to extend the ablation time again, the transition zonebetween the two ellipsoids gradually turned into a coagulation ablation zone. When theablation time was2min-4min,the growth rate of ablations volume(V), transversediameter(TD) and longitudinal diameter(LD) were the fastest, after4min the growth rategradually slowed down, after10min the growth curve gradually became flat, at the time of10min-12min,TD/LD gradually moved to1.0.At the same antenna spacing and the sametime, set ablation power were successively50W,60W,70W, the solidified form of theablation lesions were related with the ablation power(P<0.0001).With the greater power,the ablations volume(V), transverse diameter(TD) and longitudinal diameter(LD) becamebigger, but the growth rate of all indicators gradually slowed down. TD/LD close to1.0when ablation power was60W.3. When the ablation power was60W and the time was12min, the lesion morphologywas optimal and the volume was largest.CONCLUSIONS1. When the two ablation antenna spacing and the power were fixed, the longer thetime, the ablations volume(V), transverse diameter(TD) and longitudinal diameter(LD)bigger, but with the ablation time longer, all growth rates slowed down, when the ablationtime was10min,all growth rate curves gradually became flat.2. When the two ablation antenna spacing and time were fixed, the greater the power,the ablations volume(V), transverse diameter(TD) and longitudinal diameter(LD) bigger,but with the power increasing, all growth rates slowed down. 3. When the power was60W and the time was12min, we got the best ablation formand the largest volume.