The <i>in vivo</i> performance of a novel thermal accelerant agent used for augmentation of microwave energy delivery within biologic tissues during image-guided thermal ablation: a porcine study

Park, William Keun Chan; Maxwell, Aaron W.P.; Frank, Victoria; Primmer, Michael Patrick; Paul, Jarod B.; Collins, Scott; Lombardo, Kara; Lu, Shaolei; Borjeson, Tiffany M.; Baird, Grayson L.; Dupuy, Damian E.

doi:10.1080/02656736.2017.1317367

Cited by 9 publications

(6 citation statements)

References 30 publications

(34 reference statements)

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“…However, they used a different concomitant agent (triphenyl tetrazolium chloride), microwave ablation (MWA), and they injected the concomitant agent before MWA. They have also showed that there was an increase in ablation volumes with the use of concomitant agents 29 . Moreover, they have defined three distinct zones: a zone of complete desiccation named zone 1; a zone of nonviable tissue but with retained lobular architecture named zone 2; and a zone of thin rim of congestion named zone 3.…”

Section: Discussionmentioning

confidence: 98%

Percutaneous ultrasound guided PEG-coated gold nanoparticles enhanced radiofrequency ablation in liver

Mocan

Știufiuc

Popa

et al. 2021

Sci Rep

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To investigate the effects of PEG-coated gold nanoparticles on ablation zone volumes following in vivo radiofrequency ablation of porcine liver. This prospective study was performed following institutional animal care and committee approval was used. Radiofrequency ablations were performed in the livers of ten Sus scrofa domesticus swines. During each ablation, 10 mL (mL) of Peg-coated gold nanoparticles at two different concentrations (0.5 mg/mL and 0.01 mg/mL) were injected through the electrode channel into the target zone. For the control group, 10 mL of physiological saline was used. Five to ten minutes after each ablation, contrast enhanced ultrasound (CEUS) was performed to evaluate the volume of the coagulation zone. On day five we performed another CEUS and the animals were sacrificed. Treated tissues were explanted for quantification of the ablation zones’ volumes. Hematoxylin and eosin (H&E) staining was also performed for histologic analysis. A total of 30 ablations were performed in the livers. The mean coagulation zone volume as measured by CEUS on day 5 after RFA was: 21.69 ± 3.39 cm3, 19.22 ± 5.77 cm3, and 8.80 ± 3.33 cm3 for N1, N2 and PS respectively. The coagulation zone volume after N1 and N2 treatments was significantly higher compared to PS treatment (p < 0.001 and p = 0.025 respectively). There was no difference between N1 and N2 treatment (p = 0.60). In our proof-of concept, pilot study we have shown for the first time that when injected directly into the target tissue during RFA, gold nanoparticles can substantially increase the coagulation zone.

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Section: Discussionmentioning

confidence: 98%

Percutaneous ultrasound guided PEG-coated gold nanoparticles enhanced radiofrequency ablation in liver

Mocan

Știufiuc

Popa

et al. 2021

Sci Rep

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“…Several additional challenges may occur in the clinical setting. These include heat rate reduction due to blood flow in nearby vessels [41] (it should be recalled, that this also occurs without the presence of the NPs), insufficient NPs distribution in the target region, and biocompatibility related issues. Potential solutions include attaching a targeting agent to the NPs, to increase delivery efficiency to the tumour and utilising cloaking materials (such as polymers and liposomes), which may mitigate potential toxicity.…”

Section: Discussionmentioning

confidence: 99%

Target visualisation and microwave hyperthermia monitoring using nanoparticle-enhanced transmission ultrasound (NETUS)

Perlman

Weitz

Azhari

2017

International Journal of Hyperthermia

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Purpose: The aim of this study was to examine the feasibility of using nanoparticle-enhanced transmission ultrasound (NETUS) as an image-based monitoring modality for microwave hyperthermia treatment. Methods: A dedicated transmission ultrasound imaging system was used to obtain acoustic projections and ultrasound computed tomography images. Initially, speed-of-sound based images were used to non-invasively monitor temperature changes in in vitro and ex vivo specimens, induced by a microwave needle-type applicator. Next, the hyperthermia acceleration ability of two ultrasound nanoparticles based contrast agents (iron oxide and copper oxide) was examined and visualised. Finally, a two-step image guided microwave therapeutic procedure using NETUS was investigated in a realistic breast mimicking phantom. First, the pathology simulating region borders were detected. Then, a microwave-induced temperature elevation was non-invasively monitored. Results: The transmission ultrasound scanning system was able to detect temperature changes with a resolution of less than 0.5 C, both in vitro and ex vivo. In accordance with previous studies, it was visually demonstrated that iron oxide nanoparticles expedite the heating process (p < 0.05). Copper oxide nanoparticles, however, did not alter the hyperthermia profile significantly. In the breast mimicking phantom, NETUS yielded accurate detection of the target region as well as thermal monitoring of the microwave heating procedure. Conclusions: NETUS can combine enhanced target visualisation with non-invasive thermometry and accelerated heating effect. Quantitative feedback, however, requires a tissue-specific calibration-curve. A proof of concept for microwave hyperthermia treatment monitoring using NETUS was established. The suggested methodology may potentially provide a non-invasive cost-effective means for monitoring thermal treatment of the breast.

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“…The thermal accelerant (Heatsync; Theromics, West Bridgewater, Mass) is a proprietary protein-based formulation that functions through the augmentation of microwave energy transmission in the region of the ablation antenna, leading to faster tissue heating, higher ablation zone temperature, and enhanced thermal cytotoxicity (15,16). The thermal accelerant exists as a translucent gel at both room and body temperature with a measured viscosity of 3.48 kg/m/sec 6 0.08.…”

Section: Thermal Accelerantmentioning

confidence: 99%

“…To address these challenges, our laboratory has developed a thermal accelerant gel formulated to improve the transmission of microwave energy in biologic tissues. Preliminary in vivo trials have found a significant effect of thermal accelerant use in porcine muscle and liver, with observed ablation zone volume enlargement of 69.7% and 57.2%, respectively (15,16). To our knowledge, the thermal accelerant has not been previously evaluated in the lung, however, and its effects therein remain unknown.…”

mentioning

confidence: 98%

“…For the purposes of this study, the lungs were grossly divided into quadrants without respect to lobar anatomy (ie, right and left, upper and lower) and a maximum of one ablation per quadrant was attempted in each animal. An injected gel volume of 2 mL was used for each thermal accelerant ablation, twice the volume used in previous in vivo trials in the liver (15) because of the expected dispersion of gel within the air-filled spaces of the lung.…”

mentioning

confidence: 99%

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Effects of a Thermal Accelerant Gel on Microwave Ablation Zone Volumes in Lung: A Porcine Study

et al. 2019

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Background: Thermal ablation of cancers may be associated with high rates of local tumor progression. A thermal accelerant gel has been developed to improve the transmission of microwave energy in biologic tissues with the aim of enlarging the thermal ablation zone. Purpose: To determine the effects of a thermal accelerant gel on microwave ablation zone volumes in porcine lung and to compare percutaneous and endobronchial delivery methods. Materials and Methods: Thirty-two consecutive microwave lung ablations were performed in nine 12-week-old domestic male swine under general anesthesia by using fluoroscopic guidance between September 2017 and April 2018. Experimental ablations were performed following percutaneous injection of thermal accelerant into the lung (n = 16) or after endobronchial injection by using a flexible bronchoscope (n = 8). Control ablations were performed without accelerant gel (n = 8). Lung tissue was explanted after the animals were killed, and ablation zone volumes were calculated as the primary outcome measure by using triphenyltetrazolium chloride vital staining. Differences in treatment volumes were analyzed by generalized mixed modeling. Results: Thermal accelerant ablation zone volumes were larger than control ablations (accelerant vs control ablation, 4.3 cm 3 [95% confidence interval: 3.4, 5.5] vs 2.1 cm 3 [95% confidence interval: 1.4, 2.9], respectively; P , .001). Among ablations with the thermal accelerant, those performed following percutaneous injection had a larger average ablation zone volume than those performed following endobronchial injection (percutaneous vs endobronchial, 4.8 cm 3 [95% confidence interval: 3.6, 6.4] vs 3.3 cm 3 [95% confidence interval: 2.9, 3.8], respectively; P = .03). Ablation zones created after endobronchial gel injection were more uniform in size distribution (standard error, percutaneous vs endobronchial: 0.13 vs 0.07, respectively; P = .03). Conclusion: Use of thermal accelerant results in larger microwave ablation zone volumes in normal porcine lung tissue. Percutaneous thermal accelerant injection leads to a larger ablation zone volume compared with endobronchial injection, whereas a more homogeneous and precise ablation zone size is observed by using the endobronchial approach.

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The in vivo performance of a novel thermal accelerant agent used for augmentation of microwave energy delivery within biologic tissues during image-guided thermal ablation: a porcine study

Cited by 9 publications

References 30 publications

Percutaneous ultrasound guided PEG-coated gold nanoparticles enhanced radiofrequency ablation in liver

Percutaneous ultrasound guided PEG-coated gold nanoparticles enhanced radiofrequency ablation in liver

Target visualisation and microwave hyperthermia monitoring using nanoparticle-enhanced transmission ultrasound (NETUS)

Effects of a Thermal Accelerant Gel on Microwave Ablation Zone Volumes in Lung: A Porcine Study

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