A medical tactile sensing instrument for detecting embedded objects, with specific application for breast examination

摘要

BACKGROUND: In this paper, having considered the tactile sensing and palpation of a physician in order to detect abnormal masses in the breast, we simplified and then modelled the tissue containing a mass and used contact elements to analyse the tactile sensor function. METHODS: By using the finite element method, the effects of the mass existence appeared on the surface of the tissue. This was due to exerting mechanical load on the modelled tissue surface. Following this, a tactile sensing instrument called the 'tactile tumour detector' (TTD) was designed and constructed. This device is able to detect abnormal objects in the simulated models by making contact with model surfaces. In order to perform a series of precise experiments, a robot that could hold the tactile probe was used. The velocity of the linear movement of the probe is low enough to ensure that the tissue behaves in the linear elastic range, so that dynamic effects can be neglected. RESULTS AND DISCUSSION: The maximum value of stresses was chosen as the comparison criterion. The variation of this criterion vs. the mass parameter changes was investigated and good agreements between numerical and experimental results were obtained. Moreover, the sensitivity and specificity of TTD and clinical breast examination (CBE) in the detection of breast masses, in comparison to sonography as the 'gold standard', were calculated by performing clinical trials on 55 cases.