An in silico assessment on the potential of using saline infusion to overcome non-confluent coagulation zone during two-probe, no-touch bipolar radiofrequency ablation of liver cancer
- Authors: Yip, Wai , Kho, Antony , Ooi, Ean , Ooi, Ean Tat
- Date: 2023
- Type: Text , Journal article
- Relation: Medical Engineering and Physics Vol. 112, no. (2023), p.
- Full Text: false
- Reviewed:
- Description: No-touch bipolar radiofrequency ablation (bRFA) is known to produce incomplete tumour ablation with a ‘butterfly-shaped’ coagulation zone when the interelectrode distance exceeds a certain threshold. Although non-confluent coagulation zone can be avoided by not implementing the no-touch mode, doing so exposes the patient to the risk of tumour track seeding. The present study investigates if prior infusion of saline into the tissue can overcome the issues of non-confluent or butterfly-shaped coagulation. A computational modelling approach based on the finite element method was carried out. A two-compartment model comprising the tumour that is surrounded by healthy liver tissue was developed. Three cases were considered; i) saline infusion into the tumour centre; ii) one-sided saline infusion outside the tumour; and iii) two-sided saline infusion outside the tumour. For each case, three different saline volumes were considered, i.e. 6, 14 and 22 ml. Saline concentration was set to 15% w/v. Numerical results showed that saline infusion into the tumour centre can overcome the butterfly-shaped coagulation only if the infusion volume is sufficient. On the other hand, one-sided infusion outside the tumour did not overcome this. Two-sided infusion outside the tumour produced confluent coagulation zone with the largest volume. Results obtained from the present study suggest that saline infusion, when carried out correctly, can be used to effectively eradicate liver cancer. This presents a practical solution to address non-confluent coagulation zone typical of that during two-probe bRFA treatment. © 2023 IPEM
The effects of vaporisation, condensation and diffusion of water inside the tissue during saline-infused radiofrequency ablation of the liver: A computational study
- Authors: Kho, Antony , Ooi, Ean , Foo, Ji , Ooi, Ean Tat
- Date: 2022
- Type: Text , Journal article
- Relation: International journal of heat and mass transfer Vol. 194, no. (2022), p. 123062
- Full Text: false
- Reviewed:
- Description: •Effect of vaporisation, condensation & diffusion on saline-infused RFA was studied.•Condensation significantly affects the prediction of the RFA treatment outcome.•Water diffusion is insignificant when compared to condensation.•The model serves as benchmark for the accurate modelling of saline-infused RFA. [Display omitted] Saline-infused radiofrequency ablation (RFA) is a thermal ablation technique that combines saline infusion and Joule heating to destroy cancer tissues. During treatment, the intense heat generated can cause water from the infused saline and inside the tissue to vaporise. Conventionally, the effects of vaporisation have been modelled by adopting the apparent heat capacity method. However, this approach does not account for the loss of water content during vaporisation, which raises questions on its accuracy, primarily because of the large water content present during saline-infused RFA. To address this, the present study proposes an alternative approach to model vaporisation effects during saline-infused RFA. The approach adopts and modifies the water fraction method to account for the effects of vaporisation, condensation and diffusion of water inside the tissue during saline-infused RFA. The framework was compared against the commonly used apparent heat capacity method through numerical simulations carried out on 3D finite element models of the liver. Results indicated that unlike condensation, the role of diffusion of water during saline-infused RFA was not as significant as condensation, where the latter was found to affect the ablation process. With the water fraction method, there was a trend of exponential decrease in tissue electrical conductivity with time, which ultimately led to the prediction of smaller coagulation volume than that of the apparent heat capacity method.