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

Abstract

This paper demonstrates the outcomes of a feasibility study of a microwave imaging procedure based on the Huygens principle for bone lesion detection. This study has been performed using a dedicated phantom and validated through measurements in the frequency range of 1–3 GHz using one receiving and one transmitting antenna in free space. Specifically, a multilayered bone phantom, which is comprised of cortical bone and bone marrow layers, was fabricated. The identification of the lesion’s presence in different bone layers was performed on images that were derived after processing through Huygens’ principle, the S21 signals measured inside an anechoic chamber in multi-bistatic fashion. The quantification of the obtained images was carried out by introducing parameters such as the resolution and signal-to-clutter ratio (SCR). The impact of different frequencies and bandwidths (in the 1–3 GHz range) in lesion detection was investigated. The findings showed that the frequency range of 1.5–2.5 GHz offered the best resolution (1.1 cm) and SCR (2.22 on a linear scale). Subtraction between S21 obtained using two slightly displaced transmitting positions was employed to remove the artefacts; the best artefact removal was obtained when the spatial displacement was approximately of the same magnitude as the dimension of the lesion.

UWB-Printed Rectangular-Based Monopole Antenna for Biological Tissue Analysis

“…Due to these disadvantages, in recent years, some alternative techniques to traditional methods of detecting breast cancer have been carried out. One of these alternatives is the use of techniques for the analysis of biological tissues and medical imaging based on microwave signals, which have a low manufacturing cost and use non-ionizing waves [4]. These techniques are based on obtaining a diagnosis from the different response to the signals presented by healthy and tumorous breast tissues in the microwave range, mainly due to the different dielectric properties of these tissues [5].…”

“…The microwave tomography technique is based on making images from the different dielectric profiles of the tissues that are inside the breast. Furthermore, the microwave radar technique performs a mapping of the dielectric dispersion of the breast tissues [3,4]. The latter method is more computationally efficient [5].…”

Free-Space Operating Microwave Imaging Device for Bone Lesion Detection: A Phantom Investigation

“…Recent applications have been proposed for bone imaging: for instance, the authors in [8] designed a microwave scanning system which consists of an antenna array immersed in a matching liquid. Bone lesion detection through microwave imaging has also been investigated via phantom measurements in an anechoic chamber, using two antennas in free space employing an imaging procedure based on Huygens principle [9]. Recently, a portable microwave imaging device, operating in free space with two azimuthally-rotating antennas has been constructed and used for breast cancer detection [10].…”

“…In this context, multilayered phantoms mimicking bone fractures or bone marrow lesions are realized using millimetric, cylindrically shaped inclusions to emulate lesions. An artefact removal procedure has been completed using a rotation subtraction method [9] comprising performing imaging after subtracting two measurements collected using two slightly displaced transmitting positions. Subsequently, a rigorous image quantification procedure has been implemented to assess the detection capability in two scenarios, i.e., bone fracture and bone marrow lesion.…”

“…flatshaped. It is worthwhile to point out that the capability of Huygens principle-based microwave imaging to detect bone lesions was first demonstrated through phantom measurements inside an anechoic chamber [9]; here instead we performed a phantom investigation using a microwave imaging device (named MammoWave, shown in Fig. 1(a)) [10].…”