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Objectives: To study the relationship between the ablation range and applied energy of laser ablation (LA) and microwave ablation (MWA) in papillary thyroid microcarcinoma (PTMC)., Methods: A total of 201 PTMC patients were treated with LA (n = 102) or MWA (n = 99) with single-applicator fixed ablation. The ablation range was determined by contrast-enhanced ultrasound. The ratios of ablation volume, longitudinal diameter, and orthogonal diameter to ablation energy (R AV/E , R AL/E , R AO/E ) were analyzed and compared between MWA and LA. The effects of PTMC characteristics and Hashimoto's thyroiditis (HT) on ablation efficiency were evaluated by linear regression., Results: The R AV/E was 0.72 (0.65-0.84) mm 3 /J for MWA and 0.48 (0.39-0.54) mm 3 /J for LA. HT was significantly correlated with R AV/E of LA (coefficient =  - 0.367, p < 0.0001). R AL/E did not differ significantly between MWA and LA (MWA 0.026 mm/J, LA 0.025 mm/J; p = 0.957). However, MWA had a greater R AO/E than LA (MWA 0.014 mm/J, LA 0.012 mm/J; p < 0.0001). The plateau values of MWA and LA on the ablation orthogonal diameter were 10.7 mm and 8.69 mm, respectively., Conclusions: MWA showed a higher R AV/E than LA. More intuitively, MWA had a better ablation performance than LA on the orthogonal axis rather than the longitudinal axis. Theoretically, MWA and LA could achieve complete ablation of ≤ 6.70 mm and ≤ 4.69 mm PTMC separately by single-applicator fixed ablation considering a unilateral 2-mm safe margin. HT had a negative effect on LA but not on MWA., Clinical Relevance Statement: This study establishes strong connections between ablation energy and ablation range in papillary thyroid microcarcinoma (PTMC) in vivo, possibly contributing to the supplementation of the PTMC Ablation Consensus or Guidelines and providing a scientific basis for choosing clinical ablation parameters in PTMC., Key Points: • Both microwave ablation (MWA) and laser ablation (LA) have excellent performance on the ablation longitudinal axis (easily exceeding 10 mm) for papillary thyroid microcarcinoma (PTMC). • MWA performed much better than LA on the ablation orthogonal axis. • MWA and LA are expected to achieve complete ablation of ≤ 6.70 mm and ≤ 4.69 mm PTMC separately by single-applicator fixed ablation considering a unilateral 2-mm safe margin., (© 2024. The Author(s).)

Objectives: This study aimed to explore the interactions between microbubbles and microwave ablation (MWA)., Methods: The study employed custom-made phantoms (in vitro) and white New Zealand rabbits (in vivo). MWA was performed with or without microbubbles in the phantoms (2 × 10 5 particles mL -1 ) and rabbit livers (intravenous injection of 0.05 mL/kg SonoVue). During the MWA, K-type thermocouple probes were used to monitor the MWA-induced temperature increase. Contrast-enhanced ultrasound imaging (CEUS) was used to monitor and analyze the microbubbles signal intensity. After MWA, the ablation-zone volumes were evaluated and compared between the groups with and without microbubbles., Results: In both the phantom models and rabbits, microbubbles showed no significant influence on MWA, including the ablation range and MWA-induced temperature increase. In phantoms and rabbit livers filled with microbubbles, MWA caused the formation of a gradually expanding microbubble-defect region over the ablation time. An increase in the temperature caused microbubble destruction., Conclusions: Microbubbles had no significant influence on MWA. However, MWA induced the destruction of microbubbles in a temperature-dependent manner. Thus, the poor thermotolerance of microbubbles is a non-negligible barrier when using CEUS to monitor the ablation range during MWA in real-time., (© 2024 American Institute of Ultrasound in Medicine.)

[Display omitted] • Proposing a general strategy towards microwave-sensitive immune hydrogel. • Exhibiting large-scale production potential due to the mix-and-use manner. • Enabling both enhanced microwave ablation and robust antitumor immunity. • Achieving both elimination of primary tumor and inhibition of metastatic tumor. • Showing promising clinical translation due to the all FDA-approved components. The minimal invasive percutaneous microwave ablation (MWA) combined with immunotherapy is a promising technique in clinic for the treatment of primary and metastatic tumors. However, elaborate encapsulation carrier designs, complex cellular engineering, and poor applicability are the vexing problems difficult to solve currently. Herein, a general strategy was proposed for the design of an injectable microwave-sensitive immune hydrogel for combined MWA and immunotherapy in vivo for the first time. The mix-and-use hydrogel composed Food and Drug Administration (FDA)-approved components were fabricated by introducing various immunostimulants regardless of hydrophilicity and hydrophobicity into the alginate (ALG)-Ca2+ hydrogel. As a proof of concept, an immunoadjuvant (R837) was employed to synthesize the R837-ALG-hydrogel for systematic studies. This immune hydrogel owns ultra-facile synthesis process, good microwave-sensitivity, adjuvant encapsulation efficiency of nearly 100%, good biocompatibility and syringeability, and large-scale production capability, which could be easily injected into the primary tumor for enhancing MWA. Moreover, the loaded R837 could motivate in situ vaccination by making the utmost of the tumor-associated antigens released after MWA, thereby inducing the robust tumor-specific antitumor immunity to suppress the distant metastatic tumor in vivo. The proposed injectable microwave-sensitive immune hydrogel paves a facile but general avenue with great clinical translation potential for the minimal invasive personalized oncotherapy. [ABSTRACT FROM AUTHOR]