Dual-mode microwave applicator for diagnosis and thermal ablation treatment of organic tissue

对于微波消融治疗，建议的双模敷贴器提供了额外的传感模式，以改进在目标组织中的定位程序和精确的肿瘤定位。此外，涂布器将与MRI兼容，因此，通过将MR成像与集成在涂布器中的微波传感相结合，可以实现多模式成像的概念。除了创伤小、治疗时间短等优点外，它还可以在不需要CT成像的情况下进行消融治疗，从而避免了患者和放射科医生的辐射暴露。为了优化双模敷贴器的设计，在Essence的第一阶段中引入的烧蚀仿真模型将进一步发展为双向仿真，其中考虑了烧蚀过程中受影响的介电常数和对流系数等与温度相关的组织特性。对于涂抹器测试实验，需要一个可重复使用的凝胶模型，该模型在介电常数和凝血行为方面模仿人类肝脏，以避免在人类或动物身上进行实验。因此，在第一个项目阶段开发的体模的基础上，将产生一个新的体模版本，它满足进一步的标准，即肝脏等效。最后，将提供一个完整的肝脏模型，用于使用涂抹器进行可重复性的实验。为了在敷贴器插入过程中获得有关组织状态的反馈，将开发一种量身定制的校准程序，该程序将预先应用于治疗。当敷贴器在组织内移动时，该程序允许检测介电对比度。一旦敷贴器靠近肿瘤组织，其位置将被显示给用户。将对涂抹器进行磁共振成像伪影以及磁共振扫描仪的微波和电磁场之间的相互作用的测试。此外，MRI测温将在MR引导的消融过程中进行应用和测试。这样，就会对涂抹器的MRI兼容性采取适当的措施。完整的敷贴器样机最终将在临床条件下应用于MR引导的体外猪肝标本和切除的人肝组织的消融实验，以评估针在组织中的处理和定位。据我们所知，本项目中提出的具有诊断特征的新型双模微波消融装置以前只有我们的团队在文献中报道过。未来，研制的双模微波辐射器将显著提高微波消融治疗的疗效，并将朝着提供根治性治疗而不仅仅是作为姑息治疗的方向迈进一步。

For microwave ablation treatments, the proposed dual-mode applicator provides an additional sensing mode to improve the positioning procedure in the targeted tissue and precise tumor localization. Furthermore, the applicator will be MRI-compatible and thus, the concept of the multimodality imaging can be realized by combining the MR imaging with microwave sensing integrated in the applicator. In addition to the advantages like minimal-invasiveness and shorter therapy durations, it allows for an ablation therapy without need for the CT imaging, and hence, the avoidance of the radiation exposure for patients and the radiologist. For optimization of the dual-mode applicator design, the ablation simulation model introduced in the first phase of ESSENCE will be further developed towards a bidirectional simulation taking into account the temperature-dependent tissue properties among them the dielectric permittivity and convective flow coefficient that are influenced during the ablation procedure. For the applicator test experiments, a reproducible gel phantom is required which mimics the human liver regarding the dielectric permittivity and the coagulation behavior in order to avoid experiments in humans or animals. Therefore, on the basis of the phantom developed during the first project phase, a new phantom version will be produced which fulfills further criteria to be liver-equivalent. Finally, a complete liver model will be provided for reproducible experiments with the applicator. In order to get feedback about the tissue state during the applicator insertion, a tailored calibration procedure will be developed that is applied in advance to the treatment. This procedure allows the detection of dielectric contrasts when the applicator moves within the tissue. Once the applicator is in the vicinity of tumorous tissue, its position will be displayed to the user. The applicator will be tested regarding MR imaging artifacts and interaction between the microwaves and the electromagnetic fields of the MRI scanner. Furthermore, the MRI thermometry will be applied and tested during the MR-guided ablation procedure. In this way, appropriate measures will be taken concerning the MRI-compatibility of the applicator. The complete applicator prototype will be finally applied under clinical conditions in MR-guided ablation experiments to ex-vivo pig liver samples and resected human liver tissue in order to evaluate the handling and positioning of the needle in the tissue.To the best of our knowledge, the novel dual-mode microwave ablation device with diagnostic features proposed in the current project has been previously reported in literature only by our groups. In future, the developed dual-mode microwave applicator will significantly improve the efficacy of the microwave ablation therapy and will be a step forward to provide curative therapies instead of being applied only as palliative care.