Characterization of strain microgauges for the monitoring of the deformations of a medical needle during its insertion in human tissues

Abstract

International audienceFurther to the first fabrication of strain microgauges on cylindrical metal substrates [1], that we cannot experiment because of problems of wire bonding, we have reviewed the bonding process. These microgauges enable the real-time measurement of the medical needle strain distribution from which its deflection status can be deduced. So this paper deals with the new bonding process of the microgauges and the detailed experimentations. These experimentations consist in constrain the needle and verify that we can measure the strain. They allow also the calculations and the comparison of the theoretical and experimental gauge factor. Finally we discuss about the improvement of the prototype in terms of optimization of the process. Finally some material questions must find solution

Strain Gauges Based 3D Shape Monitoring of Beam Structures Using Finite Width Gauge Model

“…The approach and model presented here are particularly suitable for applications monitoring beam undergoing 3D deformations with strain gauges of significant size compared to the structure. In the medical field for instance, needle shape monitoring from strain gauges, such as in Hammond et al [38] and Bonvilain et al [39] is a potential domain of application for the work presented in this paper.…”

Geometry-Based Model for U-Shaped Strain Gauges on Medical Needles

“…A recent technique, proposed to calculate the deformed shape of the needle, involves the use of strain measures acquired from strain sensors on the surface of the needle. Different kinds of strain sensors can be used such as Fiber Bragg gratings [1], [4], [5], [7] or strain gauges as in the work of Bonvilain et al [2] and Hammond et al [3].…”

“…In the case of strain gauge technology, the U-shaped gauges are printed [3] or micro-etched [2] parallel to the needle in order to measure the axial strain on the surface, as illustrated in Fig. 1.…”

“…According to the size of the gauge, hypothesis can be made on the dimensions to be considered. Thus, the length of the gauge can be taken into account [3] or not [2], depending on whether it is negligible compared to the length of the needle. The width of the gauge, however, is not taken into consideration in the work of Bonvilain et al [2] and Hammond et al [3].…”

“…Thus, the length of the gauge can be taken into account [3] or not [2], depending on whether it is negligible compared to the length of the needle. The width of the gauge, however, is not taken into consideration in the work of Bonvilain et al [2] and Hammond et al [3]. This paper presents a model for U-shaped strain gauges which takes into account the incurved width of the gauge on the needle surface.…”