Bini Fabiano, Pica Andrada, Marinozzi Franco, Giusti Alessandro, Leoncini Andrea, Trimboli Pierpaolo
Department of Mechanical and Aerospace Engineering, Sapienza University of Rome, 00184 Rome, Italy.
Department of Biomedical Sciences, University of Sassari, 07100 Sassari, Italy.
Bioengineering (Basel). 2023 Oct 17;10(10):1210. doi: 10.3390/bioengineering10101210.
Radiofrequency (RF) ablation represents an efficient strategy to reduce the volume of thyroid nodules. In this study, a finite element model was developed with the aim of optimizing RF parameters, e.g., input power and treatment duration, in order to achieve the target volume reduction rate (VRR) for a thyroid nodule. RF ablation is modelled as a coupled electro-thermal problem wherein the electric field is applied to induce tissue heating. The electric problem is solved with the Laplace equation, the temperature distribution is estimated with the Pennes bioheat equation, and the thermal damage is evaluated using the Arrhenius equation. The optimization model is applied to RF electrode with different active tip lengths in the interval from 5 mm to 40 mm at the 5 mm step. For each case, we also explored the influence of tumour blood perfusion rate on RF ablation outcomes. The model highlights that longer active tips are more efficient as they require lesser power and shorter treatment time to reach the target VRR. Moreover, this condition is characterized by a reduced transversal ablation zone. In addition, a higher blood perfusion increases the heat dispersion, requiring a different combination of RF power and time treatment to achieve the target VRR. The model may contribute to an improvement in patient-specific RF ablation treatment.
射频（RF）消融是一种减少甲状腺结节体积的有效策略。在本研究中，开发了一个有限元模型，旨在优化射频参数，如输入功率和治疗持续时间，以实现甲状腺结节的目标体积缩小率（VRR）。射频消融被建模为一个耦合电热问题，其中施加电场以诱导组织加热。用电场问题通过拉普拉斯方程求解，温度分布用彭尼斯生物热方程估计，热损伤用阿伦尼乌斯方程评估。将优化模型应用于活性尖端长度在5毫米至40毫米之间、步长为5毫米的不同射频电极。对于每种情况，我们还探讨了肿瘤血液灌注率对射频消融结果的影响。该模型突出表明，较长的活性尖端效率更高，因为它们达到目标VRR所需的功率更小、治疗时间更短。此外，这种情况的特点是横向消融区减小。此外，较高的血液灌注会增加热扩散，需要不同的射频功率和治疗时间组合才能达到目标VRR。该模型可能有助于改善针对患者的射频消融治疗。
