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 902–928 MHz system (24 W, 5 min) and a 2450 MHz system (180 W, 2 min). Nonlinear regression analysis of temperature changes measured 5 mm from the antenna axis was completed for the initial 10 s of ablation using the power equation ΔT=at b and 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 (902–928 MHz: 0.0299 ± 0.027, 2450 MHz: 0.1598 ± 0.158), indicating proportionality to the heat source, but ‘b’ did not (902–928 MHz: 1.910 ± 0.372, 2450 MHz: 2.039 ± 0.366), signifying tissue type dependence. Past the inflection point, average steady-state temperature increases were similar between systems but reached more quickly with the 2450 MHz system. Complete damage was reached at 5 mm for both systems. The 2450 MHz system produced significantly larger short axis ablations (902–928 MHz: 2.40 ± 0.54 cm, 2450 MHz: 3.32 ± 0.41cm). Conclusion: The 2450 MHz system achieved similar steady state temperature increases compared to the 902–928 MHz 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.
| Original language | English (US) |
|---|---|
| Journal | International Journal of Hyperthermia |
| DOIs | |
| State | Published - Jan 1 2019 |
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Keywords
- kidney
- Microwave ablation
- minimally-invasive
ASJC Scopus subject areas
- Physiology
- Physiology (medical)
- Cancer Research
Cite this
Comparison of temperature change and resulting ablation size induced by a 902–928 MHz and a 2450 MHz microwave ablation system in in-vivo porcine kidneys. / Peña, Karli; Ishahak, Matthew; Arechavala, Stacie; Leveillee, Raymond J.; Salas, Nelson.
In: International Journal of Hyperthermia, 01.01.2019.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Comparison of temperature change and resulting ablation size induced by a 902–928 MHz and a 2450 MHz microwave ablation system in in-vivo porcine kidneys
AU - Peña, Karli
AU - Ishahak, Matthew
AU - Arechavala, Stacie
AU - Leveillee, Raymond J.
AU - Salas, Nelson
PY - 2019/1/1
Y1 - 2019/1/1
N2 - 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 902–928 MHz system (24 W, 5 min) and a 2450 MHz system (180 W, 2 min). Nonlinear regression analysis of temperature changes measured 5 mm from the antenna axis was completed for the initial 10 s of ablation using the power equation ΔT=at b and 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 (902–928 MHz: 0.0299 ± 0.027, 2450 MHz: 0.1598 ± 0.158), indicating proportionality to the heat source, but ‘b’ did not (902–928 MHz: 1.910 ± 0.372, 2450 MHz: 2.039 ± 0.366), signifying tissue type dependence. Past the inflection point, average steady-state temperature increases were similar between systems but reached more quickly with the 2450 MHz system. Complete damage was reached at 5 mm for both systems. The 2450 MHz system produced significantly larger short axis ablations (902–928 MHz: 2.40 ± 0.54 cm, 2450 MHz: 3.32 ± 0.41cm). Conclusion: The 2450 MHz system achieved similar steady state temperature increases compared to the 902–928 MHz 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.
AB - 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 902–928 MHz system (24 W, 5 min) and a 2450 MHz system (180 W, 2 min). Nonlinear regression analysis of temperature changes measured 5 mm from the antenna axis was completed for the initial 10 s of ablation using the power equation ΔT=at b and 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 (902–928 MHz: 0.0299 ± 0.027, 2450 MHz: 0.1598 ± 0.158), indicating proportionality to the heat source, but ‘b’ did not (902–928 MHz: 1.910 ± 0.372, 2450 MHz: 2.039 ± 0.366), signifying tissue type dependence. Past the inflection point, average steady-state temperature increases were similar between systems but reached more quickly with the 2450 MHz system. Complete damage was reached at 5 mm for both systems. The 2450 MHz system produced significantly larger short axis ablations (902–928 MHz: 2.40 ± 0.54 cm, 2450 MHz: 3.32 ± 0.41cm). Conclusion: The 2450 MHz system achieved similar steady state temperature increases compared to the 902–928 MHz 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.
KW - kidney
KW - Microwave ablation
KW - minimally-invasive
UR - http://www.scopus.com/inward/record.url?scp=85062538579&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85062538579&partnerID=8YFLogxK
U2 - 10.1080/02656736.2019.1565788
DO - 10.1080/02656736.2019.1565788
M3 - Article
C2 - 30836034
AN - SCOPUS:85062538579
JO - International Journal of Hyperthermia
JF - International Journal of Hyperthermia
SN - 0265-6736
ER -