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Osseointegrated prostheses (OIP) are an alternative to traditional socket-based prostheses, since amputees can experience unrestricted ranges of motion and improved sensory feedback. However, the risk of infection at the tissue-OIP interface is very high. Subcutaneous infections, if undetected at an early stage, can result in prosthesis loosening, bone fracture, and OIP mechanical failure. In order to avoid such issues, most of the current OIP monitoring techniques depend on physician inspection or by conventional imaging techniques. Recent studies showed that electrical capacitance tomography (ECT), which is inherently noncontact and does not require radiation, could be potentially used for imaging OIPs. In addition, embedded passive nanocomposites interrogated by ECT could reveal pH changes indicative of infection. However, the ECT images suffer from limited resolution. Thus, this study investigated a rotational ECT (RECT) system in which the ECT electrode array is rotated with respect to the central axis of the cylindrical electrode array. It was found that RECT was capable of producing better quality images as a result of an increased number of independent boundary measurements. Furthermore, a limited region tomography algorithm (LRT) was also developed and implemented to image only the region corresponding to the OIP-tissue interface. By limiting the region of interest, the ill-posed nature of the ECT inverse problem can be significantly reduced, which results in an enhanced resolution of the reconstructed images. The advantages of such a combined RECT-LRT system was first investigated using numerical simulations. Second, to demonstrate proof-of-concept, a RECT was designed a and tested in the laboratory. Several image quality metrics were calculated to critically evaluate the RECT-LRT images as compared to conventional ECT images. The results showed that the RECT-LRT system was able to generate ECT permittivity maps with higher resolution.
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