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UWB wearable apparatus for bone fracture imaging and recovering monitoring

Periodic Reporting for period 1 - WEBOING (UWB wearable apparatus for bone fracture imaging and recovering monitoring)

Reporting period: 2018-10-01 to 2020-09-30

The low-power transmission levels of ultra wideband (UWB) technology alongside its advantageously large bandwidth makes it a prime candidate to address problems in various areas including short range high data rate communications and radar applications. In addition to these application schemes, other fields where UWB technology would be deemed appropriate are under investigation. Particularly, interest has grown in the utilization of UWB radar in medicine and healthcare applications. Wearable health-monitoring systems are becoming very popular, especially for permitting non-invasive diagnosis. Moreover, recent advances in UWB hardware technology have enabled the possibility of achieving the large bandwidth, which is required for higher resolution imaging and detection. Several unique properties of UWB, including its non-ionizing signals, low cost and the ability to penetrate through media (air, skin, bones and tissues) have transformed it into an ideal candidate to be used as a novel medical imaging technology.
UWB imaging has attracted growing attention, especially for its applicability to breast cancer detection, motivated by the significant contrast in the dielectric properties at microwave frequencies of normal and malignant tissues. Current research in UWB breast imaging can be divided mainly into microwave tomography and microwave radar techniques. Several microwave breast apparatus have been constructed; some of them are now in the clinical validation process. Recently, microwave image has also been applied for imaging of human forearms, skin cancer detection, and bone imaging. To the best of our knowledge, an UWB apparatus for the purpose of bone fracture assessment does not exist.
Extension of UWB imaging to bone fracture assessment is one goal of WEBOING. This, on an engineering side, pave the way for the construction of an apparatus, which has been designed to be portable. More in detail, a virtual array will measure the scattered signal outside the portion of the body under investigation; next, the electromagnetic field behaviour inside such body portion will be reconstructed using Huygens Principle (HP), and from such behaviour, the imaging of the bone fracture will be performed. UWB signals allow all the information in the frequency domain to be utilized by combining the information from the individual frequencies to construct a consistent image. After having performed fracture imaging, UWB signals will serve the purpose of monitoring a bone lesion by considering reflection/transmission coefficients.
The capability of Huygens principle-based microwave imaging to detect bone lesions was first demonstrated through phantom measurements in anechoic chamber.
Recently, a portable UWB imaging device for breast cancer detection, which operates in free space with two azimuthally-rotating antennas, has been constructed. Specifically, the two antennas rotate all around the breast in order to collect the signals in a multi-bistatic fashion. The device, named MammoWave, has been used so far only for breast cancer detection. Thanks to WEBOING, the device has been modified and optimized for bone lesions detection. In this context, multi-layered phantoms mimicking bone fracture or bone marrow lesion scenario have been realized, using millimetric cylindrically shaped inclusions to emulate lesions. Artefact removal procedure has been completed using many dedicated methods (such as rotation subtraction method, which consists of performing imaging after subtracting two measurements collected using two slightly displaced transmitting positions). Subsequently, a rigorous image quantication procedure has been implemented in order to assess the detection capability in two scenarios, i.e. bone fracture and bone marrow lesion. Finally, to evaluate detection capability in a more realistic scenario, measurements have been performed replacing the cylindrically- shaped inclusion with an inclusion having a high-eccentric elliptical cross-section, i.e. flat-shaped. Our results suggest that lesions of 2 mm could be detected (using the band 1-6.5 GHz), even if they might appear, in the images, larger in size. Simulations also show that Huygens principle-based phase-weighted modality leads to an improvement in resolution of approximately 30% with respect to conventional amplitude-weighted modality.
After having performed fracture imaging with the portable UWB imaging device, compact wearable antennas may be used to perform fracture monitoring, In this context, it has been shown through simulations that that two UWB antennas may serve the purpose of monitoring a bone lesion by considering reflection/transmission coefficients (the relative difference between no inclusion/large inclusion may reach up to 80%). Reflection and transmission coefficients could be categorized into different levels, and such levels may be used for performing a non-invasive bone fracture monitoring without removing the plaster cast.
"The global 3D medical imaging devices market size was estimated at $10.8 billion in 2017. It was anticipated to expand at a compound annual growth rate (CAGR) of 5.9% during the forecast period. The market is dominated by multinational companies selling consolidated products on the market. The market may be segmented into ""Device Type"" as follows: X-ray Devices, CT, Ultrasound Systems, MRI.
However, there is a revolution taking place in the practice of diagnostic imaging medicine. Hospitals and private healthcare facilities are looking for new tools and methodologies to reduce the overall burden of diagnostic imaging examinations, while expanding the population reached. To this end, safe, novel, cost-effective and easy to use imaging and monitoring techniques are greatly required and represent a new opportunity for EU.
The potential impact of WEBOING is largely in the areas of diagnostics imaging and non-destructive monitoring in a European setting, creating a world leading non-ionizing diagnostic system and the pivotally required research/business expertise. The UWB imaging device optimized during WEBOING is safe (no X-rays), portable (in order to be used in site of accidents) and it has low complexity since it employs two rotating antennas operating in free space coupled through a VNA. After having performed fracture imaging with the portable UWB imaging device, compact wearable antennas are used to perform monitoring. The proposed technique has much lower cost and environmental impact than MRI or X-rays: this makes its development of very significant relevance to the medical instrumentation industry, to medical practitioners and of course to their patients. The proposed technique unique selling propositions (USPs) are:
USP1: the excellent engineering solution leads to a safe, mobile and price-competitive device (40% less than X-rays) with very low-maintenance cost.
USP2: the absence of harmful radiations enables frequent and easy monitoring to a wider population, in any health condition.
The European Commission's Innovation Radar identified the following two innovations developed during WEBOING:
i) phase-weighted UWB imaging through Huygens Principle;
ii) UWB for the detection and monitoring of bone fracture.
These innovations ( meet the need for sector-edge imaging/monitoring devices, which are accurate, safe and easily accessible.
Thanks to WEBOING, such innovations reached TRL 6."
Final image WEBOING