Temperature monitoring inside tissue undergoing minimally invasive thermal ablation is a primary goal to improve the clinical outcomes. Existing techniques for temperature measurements, classified as invasive or contactless, have limited clinical practice applications due to several practical issues. Fiber Bragg grating sensors (FBG) can be a valid solution since they can perform accurate and multi-point temperature measurements by inserting a single and small fiber optic within the tissue. Notwithstanding, their cross-sensitivity to strain may cause measurement errors during thermal procedures. Indeed, several organs (e.g., lungs, liver, pancreas) can strain gratings due to movements caused by breathing. To date, only a few studies have specifically addressed this concern, despite the wide use of FBGs in this field. To overcome this lack, we estimated the artefact of the FBGs output in response to lungs' movements induced by breathing. This investigation was carried out by inserting FBGs within a manually ventilated lung model (ex vivo swine lungs). We measured both the lungs' movements during breathing by a Motion Capture system and the related fluctuations of the FBGs' output. Moreover, we performed the same experiments during thermal ablation of lungs to assess the mentioned artefact's influence. In this study, we demonstrated the relevance of the respiratory artefact on FBGs, and also the possibility to correct this error during thermal ablation.

中文翻译：

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用于热消融过程中温度监测的光纤布拉格光栅传感器：呼吸运动引起的伪影的实验评估


进行微创热消融的组织内部温度监测是改善临床结果的主要目标。现有的温度测量技术（分为侵入式或非接触式）由于几个实际问题而限制了临床实践应用。光纤布拉格光栅传感器 (FBG) 是一种有效的解决方案，因为它们可以通过在组织内插入单个小型光纤来执行精确的多点温度测量。尽管如此，它们对应变的交叉敏感性可能会导致热过程中的测量误差。事实上，一些器官（例如肺、肝、胰腺）可能会因呼吸引起的运动而使光栅变形。迄今为止，尽管光纤光栅在该领域得到广泛应用，但只有少数研究专门解决了这一问题。为了克服这一缺陷，我们估计了响应呼吸引起的肺部运动的光纤光栅输出的伪影。这项研究是通过将光纤光栅插入手动通气肺模型（离体猪肺）中进行的。我们通过运动捕捉系统测量了呼吸期间肺部的运动以及光纤光栅输出的相关波动。此外，我们在肺部热消融过程中进行了相同的实验，以评估上述人工制品的影响。在这项研究中，我们证明了呼吸伪影与光纤光栅的相关性，以及在热消融期间纠正此错误的可能性。