引入应变灵敏度矩阵的探针形状光纤测量方法

介入探针形状监测技术能够为医生在手术中提供重要参考信息，是保证手术安全性的必要手段。为提高介入探针形状测量精度，文中提出一种引入应变灵敏度矩阵的光纤光栅传感阵列介入探针形状测量方法。首先，基于光纤光栅传感理论，分析了植入在探针中光纤光栅波长漂移量与其应变的关系，同时引入了应变灵敏度矩阵，研究了光纤光栅中心波长漂移量与其弯曲曲率的关系。然后，推导了探针的局部单元几何参数关系和坐标转换方程，建立了基于光纤光栅的探针形状测量模型。最后，为了验证引入应变灵敏度矩阵对形状测量精度的影响，对植入光纤光栅传感阵列的介入探针进行了不同弯曲状态下的形状测量实验，对比分析了引入应变灵敏度矩阵前后形状测量的误差。实验结果表明，引入光纤光栅应变灵敏度矩阵可有效提升介入探针的测量精度，在不同弯曲情况下，介入手术探针末端偏移量平均误差降低了1.385 mm，最大误差降低了3.317 mm。文中所提出的基于光纤光栅传感阵列的形状测量方法在介入手术柔性医疗器械的形状重构方向具有广阔的应用前景。

Needle shape optical fiber measurement method introducing strain sensitivity matrix

Interventional needle shape monitoring method can provide doctors with important information during surgery and is a necessary means to ensure the safety of surgery. In order to improve interventional needle shape measurement accuracy, a fiber grating sensor (FBG) array was presented, which introduced a strain sensitivity matrix to measure the shape of the probe. Firstly, based on the theory of FBG, the relationship between the wavelength shift of the fiber grating implanted in the probe and its strain was analyzed, and the strain sensitivity matrix was introduced, the relationship between the FBG center wavelength shift and its bending curvature was studied. Then the geometric parameter relations and coordinate transformation equations of the needle's local elements were deduced, and the needle shape reconstruction model based on fiber grating was established. Finally, in order to verify the influence of introducing the strain sensitivity matrix on the shape measurement accuracy, the shape measurement experiment of the intervention needle implanted with the FBGs array under different bending states was carried out, and the error of the shape measurement before and after the strain sensitivity matrix was compared and analyzed. The experimental results show that the introduction of the FBG’s strain sensitivity matrix can effectively improve the measurement accuracy of the needle. Under different bending conditions, the average error of the end of the interventional surgical needle is reduced by 1.385 mm, and the maximum error is reduced by 3.317 mm. The shape measurement method based on FBGs array proposed in this paper has broad application prospects in the direction of shape measurement of flexible medical instruments in interventional surgery.