School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, 47500, Bandar Sunway, Selangor, Malaysia; Advanced Engineering Platform, Monash University Malaysia, Jalan Lagoon Selatan, 47500, Bandar Sunway, Selangor, Malaysia.
School of Engineering and Information Technology, Faculty of Science and Technology, Federation University, VIC, 3350, Australia.
Comput Biol Med. 2021 Oct;137:104832. doi: 10.1016/j.compbiomed.2021.104832. Epub 2021 Sep 8.
Switching bipolar radiofrequency ablation (bRFA) is a thermal treatment modality used for liver cancer treatment that is capable of producing larger, more confluent and more regular thermal coagulation. When implemented in the no-touch mode, switching bRFA can prevent tumour track seeding; a medical phenomenon defined by the deposition of cancer cells along the insertion track. Nevertheless, the no-touch mode was found to yield significant unwanted thermal damage as a result of the electrodes' position outside the tumour. It is postulated that the unwanted thermal damage can be minimized if ablation can be directed such that it focuses only within the tumour domain. As it turns out, this can be achieved by partially insulating the active tip of the RF electrodes such that electric current flows in and out of the tissue only through the non-insulated section of the electrode. This concept is known as unidirectional ablation and has been shown to produce the desired effect in monopolar RFA. In this paper, computational models based on a well-established mathematical framework for modelling RFA was developed to investigate if unidirectional ablation can minimize unwanted thermal damage during time-based switching bRFA. From the numerical results, unidirectional ablation was shown to produce treatment efficacy of nearly 100%, while at the same time, minimizing the amount of unwanted thermal damage. Nevertheless, this effect was observed only when the switch interval of the time-based protocol was set to 50 s. An extended switch interval negated the benefits of unidirectional ablation.
切换双极射频消融（bRFA）是一种用于肝癌治疗的热治疗方式，能够产生更大、更连贯和更规则的热凝结。在无接触模式下实施时，切换 bRFA 可以防止肿瘤轨迹播种；这是一种定义为癌细胞沿着插入轨迹沉积的医学现象。然而，由于电极位于肿瘤之外，无接触模式会导致明显的不必要的热损伤。据推测，如果能够定向消融，使其仅聚焦于肿瘤区域，就可以最小化不必要的热损伤。事实证明，通过部分绝缘 RF 电极的活动尖端，可以实现这一点，使电流只能通过电极的非绝缘部分进出组织。这个概念被称为单向消融，并且已经在单极 RFA 中证明了其效果。在本文中，开发了基于用于模拟 RFA 的成熟数学框架的计算模型，以研究单向消融是否可以在基于时间的切换 bRFA 期间最小化不必要的热损伤。从数值结果来看，单向消融产生了近 100%的治疗效果，同时最小化了不必要的热损伤量。然而，只有当基于时间的协议的开关间隔设置为 50 s 时，才会观察到这种效果。延长开关间隔会否定单向消融的好处。
