Ablation Performance Research Articles

Epoxidized vinyl silicone rubber-based flexible ablative material with low linear ablation rate

Thermal stability and residual content of traditional silicone rubber at very high temperature are unsatisfactory for thermal insulations. This work used anionic ring-opening polymerization to prepare epoxidized vinyl silicone rubbers with high residual content. Their structures and properties of the rubbers were evaluated. The one with 84% vinyl and 6% epoxy group showed high thermal stability in air. Epoxidized vinyl silicone rubber/carbon fiber/aramid fiber insulators showed a linear ablation rate which met the stringent ablation performance requirements for a solid motor insulation material. In addition, the thermal degradation behavior of the epoxidized vinyl silicone rubbers was investigated in detail. This work provides a strategy to develop insulation materials for solid rocket motors.

Statewide data on surgical ablation for atrial fibrillation: The data provide a path forward

ObjectiveAtrial fibrillation (AF), if left untreated, is associated with increased intermediate and long-term morbidity/mortality. Surgical treatment for AF is lacking standardization in patient selection and lesion set, despite clear support from multi-society guidelines. The aim of this study was to analyze a statewide cardiac surgery registry to establish whether or not there is an association between center volume and type of index procedure with performance of surgical ablation (SA) for AF, the lesion set chosen, and ablation technology used. MethodsAdult, first-time, nonemergency patients with preoperative AF between 2014 and 2022 excluding standalone SA procedures from a statewide registry of Society of Thoracic Surgeons data were included (N = 4320). AF treatment variability by hospital volume (ordered from smallest to largest) and surgery type were examined with χ2 analyses. Hospital-level Spearman correlations compared hospital volume with proportion of AF patients treated with SA. ResultsOverall, 37% of patients with AF were ablated at the time of surgery (63% of mitral procedures, 26% of non-mitrals) and 15% had left atrial appendage management only. There was a significant temporal trend of increasing performance of SA for AF over time (Cochran-Armitage = 27.8; P < .001). Hospital cardiac surgery volume did not correlate with the proportion of AF patients treated with SA (rs = 0.19; P = .603) with a rate of SA below the state average for academic centers. Of cases with SA (n = 1582), only 43% had a biatrial lesion set. Procedures that involved mitral surgery were more likely to include a biatrial lesion set (χ2 = 392.3; P < .001) for both paroxysmal and persistent AF. Similarly, ablation technology use was variable by type of concomitant operation (χ2 = 219.0; P < .001) such that radiofrequency energy was more likely to be used in non-mitral procedures. ConclusionsThese results indicate an increase in adoption of SA for AF over time. No association between greater hospital volume or academic status and performance of SA for AF was established. Similar to national data, the type of index procedure remains the most consistent factor in the decision to perform SA with a disconnect between AF pathophysiology and decision making on the type of SA performed. This analysis demonstrates a gap between evidence-based guidelines and real-world practice, highlighting an opportunity to confer the benefits of concomitant SA to more patients.

Influence of UO2 crystal orientation on laser ablation performance

Crystallographic orientation dependence deteriorates the performance of surface analysis methods such as secondary ion mass spectrometry (SIMS) and focused ion beam (FIB). This study explores the corresponding potential challenges of laser ablation (LA) as a powerful sampling tool for inductively coupled plasma-mass spectrometry (ICP-MS). To this end, three UO2 single crystals of different orientation as well as polycrystalline UO2 were produced and characterized. Subsequently, a ns-laser ablation system was employed to study laser-matter interaction in detail. Firing the laser continuously at 1Hz with various single shot fluence (2, 4, 6, 8, 12Jcm-2) for diverse periods created LA craters impacted by cumulative fluence between 50 and 650Jcm-2. Repeated LA experiments on the (100) plane of a UO2 single crystal at the beginning and end of the entire study revealed highly reproducible (<3%) LA rates, only limited by the fluctuation of the laser energy output of the ns-LA system. After thorough cleaning of the ablated samples, surface roughness and average depth of LA craters were determined using confocal laser scanning profilometry. Both LA rate and average depth of craters decreased exponentially with increasing single shot fluence independently of the crystal orientation. Surface roughness increased linearly with increasing cumulative fluence having largest intensification for lowest single shot fluence. Scanning electron microscope (SEM) images not only revealed the conical silhouette of LA craters, but also identified a convex meniscus at its bottom. This particular shape of the crater bottom with a deeper ring surrounding the central region is a result of melted and re-solidified UO2 generated during the LA process and the main limiting factor for the achievable depth resolution. The rapid re-solidification of the liquid phase after each single laser shot created tiles of different shape and orientation, depending on UO2 crystal orientation. Three different types of ejected particles radially distributed around the LA craters were identified by SEM, providing profound insights into laser-UO2 interaction.

Ablation behaviors and mechanism of ZrC-SiC-Si/SiC-Si double-layered coatings on C/C composite under plasma flame at 3000 °C

To improve the ablation performance of C/C composite at 3000 °C, a ZrC-SiC-Si/SiC-Si double-layered coatings (ZSS/SS) was prepared by slurry dipping-carbonization and gaseous silicon infiltration. During ablation, a competition between mechanical denudation and oxidation derived thickening occurred. The ZSS/SS coating possessed a superior ablation resistance showing lowest linear ablation rate of 0.53 µm/s in 90 s with a parabolic rate constant Kp (0.053 µm/s3). The excellent performance was attributed to good self-sealing of oxidation derived glassy, thus no micro-cracks were observed. However, the Kp became worse to be 0.131 for long-term ablation because of dominant mechanical denudation.

Thermal protection materials based on epoxy‐containing and phenyl‐containing polyhedral oligomeric silsesquioxane modified phenolic resin and phenolic resin/carbon fiber composites

AbstractEpoxy‐containing and phenyl‐containing polyhedral oligomeric silsesquioxane (EP‐POSS) and EP‐POSS modified phenolic resin (PR) was prepared, and its mechanical, thermodynamic and ablative properties were characterized. The results show that EP‐POSS can effectively improve the mechanical properties, thermal stability and ablative performance of PR. In the process of ablative, EP‐POSS decomposition forms a protective layer of silica, which covers the surface of the material, slows down the erosion of the internal material by high temperature heat flow, and effectively reduces the ablative rate of the material. EP‐POSS modified PR/CF (carbon fiber) composite was prepared and its ablative performance was studied. The results show that the modified material has excellent ablative resistance, and its linear ablative rate is close to 0.

Sublayer design and ablation resistance of CVD-TaC alternate coatings with different crystallite morphologies for C/C composites

• CVD-TaC alternate coatings with different crystallite morphologies were prepared • Combination effect of TaC crystals greatly influences the ablative performance • TaC coating with the sublayer of columnar crystals showed better ablation resistance • TaC coating containing nanocrystals was damaged by superfluous gaseous products Tantalum carbon (TaC) alternate coatings with sublayers comprised of different crystallite morphologies were prepared on carbon/carbon composites by chemical vapor deposition. Their ablative behaviors and defending mechanisms were both investigated. The specimen with the sublayer composed of columnar crystals exhibited a better ablation resistance due to the toughness enhancement induced by the laminated structure. However, the mechanical denudation of the sample only containing acicular crystals and the coating spallation caused by superfluous gaseous products of the sample with the sublayer composed of nanocrystals both indicate their inferior anti-ablation properties. It is believed that the results will be helpful for the structural design and practical application of chemical vapor deposition (CVD) alternate coatings.

Fundamental study of a femtosecond laser ablation mechanism in gold and the impact of the GHz repetition rate and number of pulses on ablation volume

In this work, we performed an experimental investigation supported by a theoretical analysis of single-shot laser ablation of gold to study the laser-matter interaction for predicting the ablation morphology and optimizing the process parameters. A set of coupled partial differential equations of the two-temperature model with dynamic optical properties and a phase explosion mechanism were used to determine the temporal and spatial evolution of the electron and lattice temperatures. The primary research focus of this work is to use the GHz frequency to investigate the ablation performance because the irradiated material is still far from thermal equilibrium during the laser-matter interaction. In contrast to conventional single-pulse laser ablation, intra-burst frequencies and the number of pulses are important factors in optimizing ablation efficiency and quality for fast material processing. Theoretical investigation revealed that the ablation volume increased due to heat accumulation, but the ablation quality decreased as the intra-burst frequencies decreased from 1000 GHz to 10 GHz. Moreover, the specific ablation volume increases with a higher burst number and lower intra-burst frequency at the expense of ablation quality.

Investigation of Electrical Properties of Iron Oxide Nanoparticles Bonded with Ionic Solutions for Microwave Ablation Systems

Microwave ablation (MWA) is known as an alternative therapy to surgery to treat tumors. However, MWA-based therapy requires advanced approaches in order to prevent causing damage to healthy tissue around the tumor and selectively target the desired area. Nanoparticles are considered promising tools in biomedicine to fulfill these requirements. This study was carried out in order to analyze the effect of iron oxide nanoparticles on the temperature increment during radiofrequency ablation therapy with different salt solutions including NaCl and KCl as inorganics, and pictic acid (IP6) as organic. Iron oxide nanoparticles (IONPs) with a size of 42 nm, a surface area of 77.1 m2/g, and a high magnetic field absorption capability of 0.893 A/m were synthesized. According to the results, the magnetic nanoparticles from the IP6 solution have a higher number of charges in the recipes, and also, they reacted faster than the commercially available salt solutions like KCl and NaCl since six NaSO3 molecules are in the content of the IP6. With the absorption of 5-20 % higher electromagnetic power density depending on the content of salt solution with IP6 leads to 7-10 % temperature increase under 59 W microwave input power with 2 minutes exposure. This results show that the novelty of a dipole-dipole interaction of organic IP6 with IONPs improve the ablation performance.

SPS densification and ablative performance of ZrB2–SiC–ZrC composites derived from the ternary powders by sol-gel

ZrB2–SiC–ZrC (ZSZ) composite ceramics were successfully prepared by sol-gel method combined with spark plasma sintering (SPS) technology. ZrB2–SiC–ZrC multiphase powders with a scale of about 100 nm were firstly synthesized by sol-gel method at 1500 °C. The sintering performance of the sol-gel powders was compared with compositionally similar commercial powders mixture by SPS. The relative densities of the corresponding target composite (ZSZ1) and reference composite (ZSZ2) were reached to 96.2% and 92% under 2000 °C/40 MPa, respectively. The densification curves indicated that the residual SiO2 and B2O3 oxides derived from the precursor triggered the liquid phase sintering mechanism of sol-gel powders above 750 °C. The removal of oxide impurities through carbothermal reduction, and the diffusion and attachment of the liquid phase at the grain boundary jointly promote the densification of ZSZ1. ZSZ1 presented better oxidation/ablation resistance than ZSZ2 during the oxyacetylene ablation tests for 200 s. The mass and line ablation rate of ZSZ1 were only −4.268 × 10−4 g/s and −8.32 × 10−3 mm/s, respectively, which is attributed to be the structure of ZrO2 fine particles uniform distributed in SiO2 melt.

A mesoscopic model of mechanical erosion for the characterization of ablation behavior of C/C woven composites

Carbon/carbon (C/C) composites suffer from the thermochemical ablation and mechanical erosion in the thermal protection system. A mathematical model describing the reaction/diffusion problem for the thermochemical ablation of C/C composites is established and numerically solved on the basis of the finite volume method and piecewise linear interface calculation. Then, a mesoscopic model including a failure criterion for the simulation of mechanical erosion of C/C woven composites is proposed. In the mesoscopic model of mechanical erosion, the mechanical erosion mechanism of C/C woven composites on the microscale is analyzed, and the mechanical erosion criterion of C/C woven composites from 2D plain woven structure is extended to 2.5D woven structure. The ablation performances of woven structures under thermochemical ablation with and without mechanical erosion criterion are compared, and the effects of weaving structure features on the ablation performances of 2.5D woven structure under simulated mechanical erosion are investigated. It shows that the mesoscopic model of mechanical erosion can well characterize the ablation behavior of C/C woven composites with different weaving forms. Some suggestions are provided for the design of C/C woven composites in the thermal protection system.

Zero‐temperature‐coefficient of capacitance in BaTiO3/PI composite films using paraffin as barrier layer

AbstractFirstly, the BaTiO3 nanoparticles were coated with a layer of paraffin, forming a core shell structure. Then, as‐prepared paraffin@BaTiO3 nanofillers were directly blended with polyimide (PI) prepolymer to fabricate paraffin@BaTiO3/PI composite films. The microstructure, thermal, and dielectric properties were investigated in detail. The surface‐modified paraffin@BaTiO3 nanoparticles exhibited a typical core shell structure with uniform and complete coverage. The char yield of the composite film with 10 wt% paraffin@BaTiO3 increased from 56.40% to 70.73%. It is obvious that the paraffin@BaTiO3 nanofillers have a positive effect on ablative performance of the composite film. Compared with pure PI, the εr of paraffin@BaTiO3/PI composites with 40% mass fraction increased from 3.41 to 9.35 (1 kHz). The tanδ of paraffin@BaTiO3/PI composites was just 0.0065 (1 kHz) when the filler loading was 40 wt%. Temperature dependency of the permittivity of the composites reveals a zero‐temperature‐coefficient from 80°C to 180°C.

Research on the thermal conductivity and ablation performance of gradient 3D woven carbon/carbon composite

This paper presents a method to manufacture gradient three-dimensional (3D) orthogonal preforms by controlling fiber tension in the flexible oriented 3D woven process (FO3DWP). The method was then adopted to fabricate three groups of gradient and uniform 3D woven preforms in order to conduct fiber volume fraction analysis. The precursors were simultaneously prepared into carbon/carbon (C/C) composites by means of the precursor infiltration and pyrolysis (PIP) process. The experimental results demonstrated that the outer interlayer distance of the gradient C/C composite was smaller than the inner interlayer distance, leading to the increase of the pore distribution diameter in gradient C/C composites. Thermal conductivity test and ablation properties test were conducted experimentally via oxyacetylene flame and transient hot-wire test, respectively. The out-of-plane thermal and ablation rate of the gradient composites were found to be lower than the ones of uniform composites. Furthermore, both the ablation resistance and the thermal conductivity increased with increasing fiber volume fraction. During the ablation test, carbon fibers in the x- and y-yarn area were shown to be able to protect the matrix and interface from further ablation, compared with the z-yarn area. Those results, successfully demonstrating the thermophysical property improvement, proved great potential of the gradient 3D woven C/C composites in aerospace applications.

Enhanced flexibility and ablative performance of silicone rubber by constructing an interpenetrating zirconium-containing polysiloxane double network

To achieve uniform distribution of heteroatoms in silicone rubber, further simultaneously improving the flexibility and ablation resistance, polydimethylsiloxane with an interpenetrating zirconium-containing double-network (Zr-PDMS) was prepared. Compared to pure PDMS, the tensile strength and elongation-at-break of Zr-PDMS with interpenetrating double-network were increased by 615.33% and 124.23%, respectively, exhibiting significantly enhanced flexibility. Ablation analysis indicated that Zr-PDMS showed excellent anti-ablation performance, exhibiting obviously decreased mass ablation rate and charring rate. Most importantly, different from the crisp charred layers of pure PDMS as well as ZrO2 blends, Zr-PDMS formed stable and coherent charred layers after ablation tests. The improvement correlated to the in-situ formation of tetragonal ZrO2 in the char layer of Zr-PDMS, which could avoid the generation of defects in the ZrO2 blends char layer were discussed in detail. This work provided a new strategy of high flexible silicon rubber with excellent ablative performance, which can be expected to be well applied in the hypersonic spacecrafts.

IMMULAB: A phase II trial of immunotherapy with pembrolizumab in combination with local ablation for patients with early-stage hepatocellular carcinoma (HCC).

555 Background: Percutaneous ablation of neoplastic tissue by radiofrequency ablation (RFA), microwave ablation (MWA) or brachytherapy is considered a potentially curative treatment for early HCC, but recurrence rates are high. Local ablative therapies release immunogenic stimuli that can trigger an anti-tumoral immune response, which is, however, dampened by counter-regulatory mechanisms mediated through immune checkpoints, such as CTLA-4 and PD-1. Combining local therapies with immunotherapies may shift the balance to a more robust immunostimulatory response. We therefore hypothesized that peri-interventional treatment with pembrolizumab may synergize with and improve outcome of local ablative therapy. Methods: This single arm phase II trial investigates peri-interventional treatment with pembrolizumab combined with RFA/MWA or brachytherapy, or - as recommended for tumors larger than 3 cm – combined with TACE and RFA/MWA or brachytherapy in early-stage HCC with maintained liver function (Child Pugh A) who did not receive prior local or systemic therapy. Pembrolizumab (200mg, q3w) was administered intravenously for 2 cycles, followed by radiologic imaging and local therapy. Pembrolizumab was continued for up to 12 months. The primary efficacy endpoint was defined as overall response rate (ORR, RECIST 1.1) after 2 cycles of pembrolizumab and before local therapy while secondary endpoints are time to recurrence (TTR, defined as the length of time after performance of local ablation resulting in confirmed absence of viable tumor tissue until documented tumor recurrence), recurrence free survival and overall survival (OS) along with safety and tolerability. Results: 30 patients (pts, ECOG 0 or 1) were enrolled in 9 centers in Germany, with a median age of 70 years and a predominance of male pts (73.3%). All pts received at least 1 dose of study treatment and the median number of cycles was 13. ORR was 13.3%, with 6.7% complete responses (CR) and 6.7% partial responses (PR) after two cycles of pembrolizumab and before local ablation. Subsequent local ablation was performed in 25/30 pts. With ongoing follow-up median of 14 months (Sep 2022), provisional median overall survival time (mOS) was not reached and provisional median time to recurrence (TTR) was 17.41 months. No new safety signs were observed. Conclusions: The study did not meet its primary endpoint. The hypothesized ORR of 30% before local therapy was not reached. However, there is evidence for the efficacy of peri-interventional treatment with pembrolizumab combined with local ablative therapy without new safety signals. Our findings support further evaluation of this combination treatment in early-stage HCC. Clinical trial information: NCT03753659 .

Multi-healing behavior of (NbC-TaC)/ZrC/SiC triple-layer coated C/C composites enduring oxyacetylene flame

Herein, the ablation resistance of plasma-sprayed TaC-modified NbC (NbC-TaC) coatings on ZrC/SiC double-layer-coated C/C composites was firstly tested using an oxyacetylene flame. Next, the phase composition of ZrO2-Ta2O5 (TaO2.5) systems heat-treated at 2100 °C in an argon atmosphere was determined. The results demonstrated the formation of a free-standing TaO film that extended the effective ablation time of the TaC coating to >90 s. Among the NbC-TaC coatings, the 37.5 mol% TaC-addition produced a continuous film, achieving the best ablation property. Multi-healing behavior, comprised of interfacial, in situ, and surficial healing, further improved ablation performance. At 2100 °C, the solubility of TaO2.5 in ZrO2 was 15 mol%, and the stable phases were tetragonal ZrO2 and Ta with face- and body-centered cubic structures. Furthermore, the interfacial bonding conditions of the heat-treated Zr-O-Ta system and the thermal stability mechanism of ZrO2 to Ta2O5 were discussed.

Studies on Ablative Performance of Silicone Low-Density Ablative Material

In the present studies, silicon based low-density ablative material has been studied for its ablative performance to protect flight hardware from temperature raises due to aerodynamic forces for a longer duration. The oxyacetylene flame test estimates ablative properties at 100–120 W/m2 heat flux. The time duration for the flame test is taken 200 s. The material shows low mass and linear ablation rate with high ablative effectiveness. The degradation kinetics of silicon ablator is studied by Thermo Gravimetric Analysis (TGA) method. Non-isothermal TGA is performed in the temperature range of 30 °C to 900 °C at various heating rates, viz. 5, 10, 15, and 20 °C/ min. Knowledge of the kinetic parameters of thermal decomposition is used to predict the degradation kinetics of the material at high heating rates, which the ablator faces during aerospace applications. During ablation, the silicone ablative material consists of a virgin zone, reaction zone, and char zone. These are explained by kinetic parameters determined with the help of free software called Kinetic Calculation.

Laser ablation mechanism of ZrC-SiC-MoSi2 ternary ceramic modified C/C

C/C composites were prepared by chemical vapor infiltration (CVI), and then were subjected to Si, Zr, and MoSi2 reactive melt infiltration (RMI) to obtain C/C-SiC, C/C-SiC-ZrC, and C/C-SiC-ZrC-MoSi2 composites. The ablation behavior of these three composites was evaluated by high-energy CO2 laser irradiation. The surface temperature distribution of composite materials was simulated by finite element analysis. The results show that the ablation resistance mechanisms of the three materials are entirely different. The C/C-SiC-ZrC-MoSi2 composite showed the best ablation performance among them. It is attributed to the lower oxygen permeability and richer heat dissipation mechanism of the C/C-SiC-ZrC-MoSi2 composite within the total temperature threshold.

The aryl-boron phenolic resins with super ablation properties for resin-transfer molding process of three-dimensional fabric

Boron phenolic resin (BPR) is one of the most extensively utilized matrix resins in ablative field due to its outstanding heat resistance and ablation performance. However, the existing BPR applications are severely limited since they are unsuited for the resin-transfer molding (RTM) process. This research created and manufactured arylboronic acid (PBA) modified phenolic resins (ABPRs) for RTM techniques. Since ABPRs maintain a low viscosity (0.8 Pa·s) throughout a wide temperature range (65–80°C), they can meet the essential criteria of co-injection RTM techniques. The inclusion of PBA significantly improved the heat and oxidation resistance of ABPRs. The char yield of PR and ABPR-d are 64.5% and 70.4%, respectively (800°C, N2 atmosphere). Three-dimensional woven carbon fiber textiles strengthen the CF/ABPR composites, which possess excellent mechanical and ablation properties. The oxygen-acetylene test revealed the mass ablation rates of CF/PR and CF/ABPR-d were 0.052 and 0.049 mm/s, respectively. Since the ABPRs for RTM developed for this work have excellent processability, thermal characteristics, mechanical properties and ablation capabilities, the resin matrix can offer excellent comprehensive attributes for the nozzle-expanding section of solid rocket motors.

Bipolar Radiofrequency Ablation of the Adrenal Gland: In Vivo and Ex Vivo Experiments.

Laparoscopic adrenalectomy is currently the standard treatment modality for unilateral aldosterone-producing adenoma (APA); however, a less-invasive treatment is needed for its treatment. A new bipolar ablation system that poses a lower risk of complications has been recently developed. This study aimed to evaluate the safety and performance of a novel bipolar radiofrequency ablation (RFA) system for the treatment of APAs. Ablations were performed in an ex vivo study using bovine adrenal glands [group A: n = 6, single-probe; group B: n = 6, two probes, interprobe distance (ID) = 12 mm; group C: n = 6, two probes, ID = 20 mm]. The in vivo study was conducted in groups A and B (n = 2 each) using porcine adrenal glands. For the ex vivo study, the mean vertical diameter (Dv) of the coagulative necrosis area and the mean transverse diameter (Dt) values were 11.99 mm and 10.96 mm for group A, 12.66 mm and 10.0 mm for group B, and 23.37 mm and 22.10 mm for group C, respectively. For the in vivo study, the mean Dv and Dt values were 12.23 mm and 9.03 mm for group A, and 16.38 mm and 9.52 mm for group B, respectively. No heat-induced damage to the adjacent organs was observed. To our best knowledge, this is the first study to evaluate the performance of the bipolar system in RFA of the adrenal gland. RFA using the new bipolar ablation system is safe and produces a sufficient coagulation area to treat APAs.

Comparison of Ablation Performance between Octopus Multipurpose Electrode and Conventional Octopus Electrode.

To compare Octopus multipurpose (MP) electrodes, which are capable of saline instillation and direct tissue temperature measurement, and conventional electrodes for radiofrequency ablation (RFA) in porcine livers in vivo. Sixteen pigs were used in this study. In the first experiment, RFA was performed in the liver for 6 minutes using Octopus MP electrodes (n = 15 ablation zones) and conventional electrodes (n = 12 ablation zones) to investigate the effect of saline instillation. The ablation energy, electrical impedance, and ablation volume of the two electrodes were compared. In the second experiment, RFA was performed near the gallbladder (GB) and colon using Octopus MP electrodes (n = 12 ablation zones for each) with direct tissue temperature monitoring and conventional electrodes (n = 11 ablation zones for each). RFA was discontinued when the temperature increased to > 60℃ in the Octopus MP electrode group, whereas RFA was performed for a total of 6 minutes in the conventional electrode group. Thermal injury was assessed and compared between the two groups by pathological examination. In the first experiment, the ablation volume and total energy delivered in the Octopus MP electrode group were significantly larger than those in the conventional electrode group (15.7 ± 4.26 cm3 vs. 12.5 ± 2.14 cm3, p = 0.027; 5.48 ± 0.49 Kcal vs. 5.04 ± 0.49 Kcal, p = 0.029). In the second experiment, thermal injury to the GB and colon was less frequently noted in the Octopus MP electrode group than that in the conventional electrode group (16.7% [2/12] vs. 90.9% [10/11] for GB and 8.3% [1/12] vs. 90.9% [10/11] for colon, p < 0.001 for all). The total energy delivered around the GB (2.65 ± 1.07 Kcal vs. 5.04 ± 0.66 Kcal) and colon (2.58 ± 0.57 Kcal vs. 5.17 ± 0.90 Kcal) were significantly lower in the Octopus MP electrode group than that in the conventional electrode group (p < 0.001 for all). RFA using the Octopus MP electrodes induced a larger ablation volume and resulted in less thermal injury to the adjacent organs compared with conventional electrodes.