Background/Objectives: Combining radiation therapy with mild hyperthermia, especially via magnetic resonance-guided focused ultrasound (MRgFUS), holds promise for enhancing tumor control and alleviating symptoms in cancer patients. However, current clinical applications of MRgFUS focus primarily on ablative treatments, and using MRI guidance for each radiation session increases treatment costs and logistical demands. This study aimed to test a streamlined workflow for repeated hyperthermia treatments that reduces the need for continuous MRI monitoring, using an approach based on impulse response function (Green’s function) to optimize acoustic power settings in advance.Methods: We implemented the Green’s function approach in a perfused, tissue-mimicking phantom, conducting 30 experiments to simulate hyperthermia delivery via MRgFUS. Pre-calculated acoustic power settings were applied to maintain a stable hyperthermia target without the need for real-time feedback control from MRI thermometry. Additionally, a retrospective analysis of patient thermometry data from MRgFUS sonications was performed to assess feasibility in clinical contexts.Results: Our experiments demonstrated consistent, stable hyperthermia (+7 °C) for 15 min across varying perfusion rates, outperforming conventional closed-loop MRI feedback methods in maintaining temperature stability. The retrospective analysis confirmed that this method is noise-robust and clinically applicable.Conclusions: This off-line approach to hyperthermia control could simplify the integration of MRgFUS hyperthermia in cancer treatment, reducing costs and logistical barriers. These findings suggest that our method may enable the broader adoption of hyperthermia in radiation therapy, supporting its role as a viable adjuvant treatment in oncology.
背景/目的：将放射治疗与温和热疗相结合，特别是通过磁共振引导聚焦超声（MRgFUS），有望增强肿瘤控制并缓解癌症患者的症状。然而，目前MRgFUS的临床应用主要集中在消融治疗上，且每次放射治疗均使用MRI引导会增加治疗成本和操作复杂性。本研究旨在测试一种简化的重复热疗工作流程，通过基于脉冲响应函数（格林函数）的方法预先优化声功率设置，以减少对持续MRI监测的需求。 方法：我们在灌注的组织模拟体模中应用格林函数方法，进行了30次实验以模拟通过MRgFUS实施热疗。应用预先计算的声功率设置以维持稳定的热疗目标，无需依赖MRI测温的实时反馈控制。此外，对来自MRgFUS声波处理的患者测温数据进行了回顾性分析，以评估其在临床环境中的可行性。 结果：我们的实验表明，在不同灌注率下均能实现持续、稳定的热疗（+7°C）达15分钟，在维持温度稳定性方面优于传统的闭环MRI反馈方法。回顾性分析证实，该方法具有抗噪性且适用于临床。 结论：这种离线热疗控制方法可以简化MRgFUS热疗在癌症治疗中的整合，降低成本和操作障碍。这些发现表明，我们的方法可能促进热疗在放射治疗中的更广泛应用，支持其作为肿瘤学中可行的辅助治疗手段。
Using the Tissue Impulse Response Function to Streamline Fractionated MRgFUS-Induced Hyperthermia
肿瘤(癌症)患者之家