Thermomechanical Modeling of Laser Ablation Therapy of Tumors: Sensitivity Analysis and Optimization of Influential Variables

Abstract

In cancer treatment, laser ablation is a promising technique used to induce localized thermal damage. Different variables influence the temperature distribution in the tissue and the resulting therapy efficacy; thus, the optimal therapy settings are required for obtaining the desired clinical outcome. In this work, thermomechanical modeling of contactless laser ablation was implemented to analyze the sensitivity of independent variables on the optimal treatment conditions. The Finite Element Method was utilized to solve the governing equations, i.e., the bioheat, mechanical deformation, and the Navier-Stokes equations. Validation of the model was performed by comparing experimental and simulated temperatures, which indicated high accuracy for estimating temperature. In particular, the results showed that the model can estimate temperature with a good correlation factor (R=0.98) and low Mean Absolute Error (3.9 °C). A sensitivity analysis based on laser irradiation time, power, beam distribution, and the blood vessel depth on temperature distribution and fraction of necrotic tissue was performed. An optimization process was performed based on the most significant variables, i.e., laser irradiation time and power. This resulted in an indication of the optimal therapy settings for achieving maximum procedure efficiency i.e., the required fraction of necrotic tissue within the target volume, constituted by tumor and safety margins around it.

Gold Nanoparticles-Mediated Photothermal Therapy of Pancreas Using GATE: A New Simulation Platform

“…Additionally, they provide multi-point temperature measurements using a small-sized optical fiber embedding multiple FBG sensors, thus enabling the reconstruction of the temperature profile with accuracy for each sensor of 0.1 °C. Additional details on FBG sensors are reported in the previous papers of our group [ 12 , 56 , 57 , 58 , 59 , 60 ].…”

Unscented Kalman Filtering for Real Time Thermometry During Laser Ablation Interventions

“…To obtain ground truth data, experiments have been performed on ex vivo liver tissue undergoing laser treatment. Details of the setup and trials are described in the previous work of our group [9], [17]. A network of 125 FBG sensors (5 parallel arrays, each embedded with 25 sensors) was used to measure the tissue temperature induced by the laser.…”

“…However, when the observations are not selected optimally, the value of 𝐷 decreases to 0. Since for a biological tissue, 𝐷 is typically 0.15 mm 2 /s [17], [18], we set a threshold to hold the minimum value of 𝐷. On the other hand, the value of 𝑞 tends to increase.…”

Three-Phase-Lag Bio-Heat Transfer Model of Cardiac Ablation

“…These models also assist in providing a reasonable a priori estimate of the treatment outcomes of therapy that is beneficial in optimizing the thermal dosage and better planning of the procedure, thus minimizing the risk of unnecessary damage to the surrounding healthy tissue and critical structures. Several advancements have been reported in the computational modeling of thermal ablation in the past decades to reach a stage where the discrepancy between the model outcome and experimental/clinical results is minimal [7][8][9][10][11]. So that the patient-specific models can be readily integrated within the hospital workflow to provide accurate predictions during the treatment planning stage, thereby enhancing the efficacy of such thermal therapies.…”