Microwave bone imaging: a preliminary scanning system for proof‐of‐concept

Abstract

This Letter introduces a feasibility study of a scanning system for applications in biomedical bone imaging operating in the microwave range 0.5–4 GHz. Mechanical uncertainties and data acquisition time are minimised by using a fully automated scanner that controls two antipodal Vivaldi antennas. Accurate antenna positioning and synchronisation with data acquisition enables a rigorous proof-of-concept for the microwave imaging procedure of a multi-layer phantom including skin, fat, muscle and bone tissues. The presence of a suitable coupling medium enables antenna miniaturisation and mitigates the impedance mismatch between antennas and phantom. The three-dimensional image of tibia and fibula is successfully reconstructed by scanning the multi-layer phantom due to the distinctive dielectric contrast between target and surrounding tissues. These results show the viability of a microwave bone imaging technology which is low cost, portable, non-ionising, and does not require specially trained personnel. In fact, as no a-priori characterisation of the antenna is required, the image formation procedure is very conveniently simplified.

A Phantom Investigation to Quantify Huygens Principle Based Microwave Imaging for Bone Lesion Detection

“…The authors in [18] performed a study for bone imaging, collecting the signals in multi-monostatic fashion and using antennas immersed in a coupling liquid. In [18], imaging was performed using a beamforming procedure named non-coherent migration, after applying an average trace subtraction strategy to remove the artefact.…”

“…The authors in [18] performed a study for bone imaging, collecting the signals in multi-monostatic fashion and using antennas immersed in a coupling liquid. In [18], imaging was performed using a beamforming procedure named non-coherent migration, after applying an average trace subtraction strategy to remove the artefact. Instead, here, we collect the signals in multi-bistatic fashion, using antennas in free space; imaging was performed using an HP based algorithm, which operated in the frequency domain, after applying a rotation subtraction strategy to remove the artefact.…”

“…Nevertheless, microwave tomography has its drawbacks such as low signal-to-clutter and complex mathematical formulation. Both microwave tomography and UWB radar techniques have been increasingly well investigated for stroke detection [15], breast cancer detection [16], bone imaging [17,18], and skin cancer detection [19] through using different approaches at different frequency ranges.…”

“…UWB imaging for bone lesion detection has been studied through using matching liquids [17,18]. We propose imaging execution using two antennas operating in free space.…”

“…Imaging was performed via a Huygens principle (HP) based algorithm, which was initiated originally for breast imaging. Explicitly, S21 signals in the frequency range 1-3 GHz [18] were collected in a multi-bistatic fashion in an anechoic chamber setting using a multilayer phantom, mimicking bones. A realistic multilayer bone mimicking phantom comprised of cortical bone mimicking and bone marrow mimicking layers was constructed.…”