Design of a steam thermal ablation system for liver tumors and its efficacy evaluation based on fluorescence imaging

BACKGROUND: At present, traditional minimally invasive thermal ablation technologies are all derived from electromagnetic radiation energy generated by high-frequency, high-energy physical sources. Consequently, they all share common issues, such as poor conformability, carbonization, difficulty controlling temperature, and electromagnetic radiation. METHODS: This paper proposes a steam thermal ablation (STA) technology that utilizes the internal energy of saturated steam to replace traditional electromagnetic radiation-based energy sources. Using a self-built, minimally invasive steam thermal ablation precision treatment system for liver tumors and a steam ablation needle designed via COMSOL simulation, ex vivo pig liver experiments were conducted. Based on STA characteristics, a real-time monitoring scheme for the ablation boundary has been proposed using fluorescence imaging. RESULTS: The results of STA are characterized by a maximal ablation axis ratio (short diameter/long diameter) and the absence of carbonization. The fluorescence-based monitoring effectively eliminated artifacts and radiation constraints typical of ultrasound or CT-guided procedures. CONCLUSIONS: Steam thermal ablation (STA) technology offers a novel thermal ablation method, featuring good conformability and no carbonization. Combined with real-time fluorescence imaging monitoring, it provides a feasible solution for the limitations of traditional minimally invasive thermal ablation techniques.