Three-Axis Capacitive Touch-Force Sensor for Clinical Breast Examination Simulators

Clinical breast examinations (CBEs) are a vital part of breast cancer screening programs. However, there is a lack of standardization in the kinds of motion and the forces used during the examination, which can lead to either an inaccurate or a missed diagnosis. The use of sensors in CBE simulations and training can help to alleviate this issue. This paper demonstrates a flexible, three-axis capacitive touch-force sensor that utilizes a patterned elastomeric dielectric layer. The sensor was fabricated from a copper-clad Kapton laminate and can resolve normal pressure and track directional motion. The electronic and mechanical properties of the patterned dielectric layer were analyzed in detail using finite-element analysis techniques and these results were then used to optimize the sensor. In a mock CBE setup, we used a breast model to demonstrate that the sensor, when placed under the model, could track a normal force of about 18 N when applied to the test area, as well as the trajectory of the force as it was applied around the breast model. This data, along with the accompanying variations in signal patterns, can be utilized to quantify the CBE conducted by an expert physician, which in turn can be used as feedback in training tools for residents and other physicians.