An Analysis of Microwave Ablation Parameters for Treatment of Liver Tumors from the 3D-IRCADb-01 Database

Abstract

Simulation techniques are powerful tools for determining the optimal conditions necessary for microwave ablation to be efficient and safe for treating liver tumors. Owing to the complexity and computational resource consumption, most of the existing numerical models are two-dimensional axisymmetric models that emulate actual three-dimensional cancers and the surrounding tissue, which is often far from reality. Different tumor shapes and sizes require different input powers and ablation times to ensure the preservation of healthy tissues that can be determined only by the full three-dimensional simulations. This study aimed to tailor microwave ablation therapeutic conditions for complete tumor ablation with an adequate safety margin, while avoiding injury to the surrounding healthy tissue. Three-dimensional simulations were performed for a multi-slot microwave antenna immersed in two tumors obtained from the 3D-IRCADb-01 liver tumors database. The temperature dependence of the dielectric and thermal properties of healthy and tumoral liver tissues, blood perfusion, and water content are crucial for calculating the correct ablation time and, thereby, the correct ablation process. The developed three-dimensional simulation model may help practitioners in planning patient-individual procedures by determining the optimal input power and duration of the ablation process for the actual shape of the tumor. With proper input power, necrotic tissue is placed mainly in the tumor, and only a small amount of surrounding tissue is damaged.

Computational Modeling of Microwave Tumor Ablation

“…Compared with other antenna designs (see [ 101 ] and references therein), a multi-slot coaxial antenna has a better ability to produce an optimal shape of the ablation zone pattern (see Figure 7 b) [ 101 ]. Recent simulation results have confirmed that a compact 10-slot antenna consisting of several periodic elements equivalent to a linear uniform antenna array creates near-spherical ablation zones [ 50 , 53 ]. Finely tuned impedance matching minimizes damage to the surrounding healthy tissues.…”

“…One of the most promising therapies for HCC is MWA at 2.45 GHz as a rapid treatment with a short recovery [ 9 , 113 ]. The development of mathematical models enables the determination of the optimal conditions necessary for planning patient-specific MWA procedures to be as effective as possible for treating HCC [ 50 , 53 ].…”

“…The temperature dependence of electrical conductivity and permittivity of healthy and tumoral tissues is included in the calculation of the electromagnetic field. A compact 10-slot antenna with several periodic elements ( Figure 11 ) was immersed in tissue [ 50 , 53 ].…”

“…Instead, we used realistic tumor geometry based on data from the 3D-IRCADb-01 database, which comprises several sets of patients’ CT scans manually segmented by clinical experts [ 115 ]. The simulation parameters characteristics for healthy liver, malignancy, and blood are listed in Table 1 [ 50 , 53 , 102 ].…”

“…Owing to the complexity of the models and computational resource consumption, the majority of actual numerical studies are based on two-dimensional (2D) axisymmetric models to reproduce realistic tumor shapes, which are usually non-axisymmetric [ 44 , 45 , 46 , 47 , 48 ]. Several 3D simulations have recently been performed to determine the fraction of damage during MWA of tumoral tissues [ 49 , 50 , 51 , 52 , 53 ]. The higher the level of predictability achieved in simulations, the easier it is to plan a treatment procedure that is safer, more effective, and less time-consuming.…”