%0 Journal Article %T Comparison of temperature change and resulting ablation size induced by a 902每928ˋMHz and a 2450ˋMHz microwave ablation system in in-vivo porcine kidneys %A Karli Peˋa %A Matthew Ishahak %A Nelson Salas %A Raymond J. Leveillee %A Stacie Arechavala %J International Journal of Hyperthermia %D 2019 %R https://doi.org/10.1080/02656736.2019.1565788 %X Abstract Introduction: Microwave ablation (MWA) uses heat to ablate undesired tissue. Development of pre-planning algorithms for MWA of small renal masses requires understanding of microwave-tissue interactions at different operating parameters. The objective of this study was to compare the performance of two MWA systems in in-vivo porcine kidneys. Methods: Five ablations were performed using a 902每928ˋMHz system (24ˋW, 5ˋmin) and a 2450ˋMHz system (180ˋW, 2ˋmin). Nonlinear regression analysis of temperature changes measured 5ˋmm from the antenna axis was completed for the initial 10ˋs of ablation using the power equation 忖T=atband after the inflection point using an exponential equation. Thermal damage was calculated using the Arrhenius equation. Long and short axis ablation diameters were measured. Results: The average &a* varied significantly between systems (902每928ˋMHz: 0.0299ˋ㊣ˋ0.027, 2450ˋMHz: 0.1598ˋ㊣ˋ0.158), indicating proportionality to the heat source, but &b* did not (902每928ˋMHz: 1.910ˋ㊣ˋ0.372, 2450ˋMHz: 2.039ˋ㊣ˋ0.366), signifying tissue type dependence. Past the inflection point, average steady-state temperature increases were similar between systems but reached more quickly with the 2450ˋMHz system. Complete damage was reached at 5ˋmm for both systems. The 2450ˋMHz system produced significantly larger short axis ablations (902每928ˋMHz: 2.40ˋ㊣ˋ0.54ˋcm, 2450ˋMHz: 3.32ˋ㊣ˋ0.41cm). Conclusion: The 2450ˋMHz system achieved similar steady state temperature increases compared to the 902每928ˋMHz system, but more quickly due to higher output power. Further investigations using various treatment parameters and precise thermal sensor placement are warranted to refine equation parameters for the development of an ablation model %U https://www.tandfonline.com/doi/full/10.1080/02656736.2019.1565788