Manufacturing Process Optimization of Breast Phantoms to Assess Tactile Sensing Technologies for Noninvasive Tumor Detection

Noninvasive breast palpation represents a preliminary exam for detecting alterations in tissue stiffness (e.g., tumor masses). While promising, this technique carries substantial risk of misdiagnosis, as it strongly depends on the attention and experience of the examiner. For these reasons, tactile sensors based on different technologies (e.g., piezoelectric, conductive, and fiber Bragg grating (FBG) sensors) were proposed to quantitatively identify hard inclusions within soft tissues. In this context, breast phantoms play a crucial role to design, optimize, and test the response of novel tactile sensing solutions before proceeding with high cost and time-consuming clinical trials. However, the current breast phantoms show several limitations, like the limited reproducibility and adaptability to different experimental requirements, as well as the lack of detailed information about their fabrication steps and strategies for embedding tumor masses. This study proposed an optimized fabrication process for breast phantoms. Each manufacturing step was described in detail to enhance the reproducibility and versatility of the breast models used to test tactile sensors for noninvasive tissue palpation. In particular, in this work, two breast phantoms were fabricated, embedding tumor masses with different size and depth. In addition, these phantoms were employed to validate a 3D-printed tactile sensor based on FBG-technology to assess its capability to detect tumors and distinguish their different characteristics in terms of dimensions and depths. The proposed optimized process proved effective in testing the system under the specified conditions. The promising findings lay the foundation for further optimizations toward applications in realworld scenarios.