Sumser Kemal, Drizdal Tomas, Bellizzi Gennaro G, Hernandez-Tamames Juan A, van Rhoon Gerard C, Paulides Margarethus Marius
Department of Radiotherapy, Erasmus Medical Center Cancer Institute, 3015 GD Rotterdam, The Netherlands.
Department of Biomedical Technology, Czech Technical University in Prague, nam. Sítna 3105, 272 01 Kladno, Czech Republic.
Cancers (Basel). 2021 Nov 10;13(22):5617. doi: 10.3390/cancers13225617.
Clinical effectiveness of hyperthermia treatments, in which tumor tissue is artificially heated to 40-44 °C for 60-90 min, can be hampered by a lack of accurate temperature monitoring. The need for noninvasive temperature monitoring in the head and neck region (H&N) and the potential of MR thermometry prompt us to design an MR compatible hyperthermia applicator: the MRcollar. In this work, we validate the design, numerical model, and MR performance of the MRcollar. The MRcollar antennas have low reflection coefficients (<-15 dB) and the intended low interaction between the individual antenna modules (<-32 dB). A 10 °C increase in 3 min was reached in a muscle-equivalent phantom, such that the specifications from the European Society for Hyperthermic Oncology were easily reached. The MRcollar had a minimal effect on MR image quality and a five-fold improvement in SNR was achieved using the integrated coils of the MRcollar, compared to the body coil. The feasibility of using the MRcollar in an MR environment was shown by a synchronous heating experiment. The match between the predicted SAR and measured SAR using MR thermometry satisfied the gamma criteria [distance-to-agreement = 5 mm, dose-difference = 7%]. All experiments combined show that the MRcollar delivers on the needs for MR-hyperthermia in the H&N and is ready for in vivo investigation.
热疗的临床效果可能会因缺乏精确的温度监测而受到影响，热疗是将肿瘤组织人工加热至40-44°C并持续60-90分钟。对头颈部区域（H&N）进行无创温度监测的需求以及磁共振测温的潜力促使我们设计一种与磁共振兼容的热疗施加器：MR项圈。在这项工作中，我们验证了MR项圈的设计、数值模型和磁共振性能。MR项圈天线具有低反射系数（<-15 dB），且各个天线模块之间的相互作用预期较低（<-32 dB）。在肌肉等效体模中3分钟内温度升高了10°C，轻松达到了欧洲热疗肿瘤学会的规格要求。MR项圈对磁共振图像质量的影响最小，与体线圈相比，使用MR项圈的集成线圈时信噪比提高了五倍。同步加热实验证明了在磁共振环境中使用MR项圈的可行性。使用磁共振测温法预测的比吸收率（SAR）与测量的SAR之间的匹配满足伽马标准[距离一致性=5毫米，剂量差异=7%]。所有实验综合表明，MR项圈满足了头颈部磁共振热疗的需求，已准备好进行体内研究。
