Determining bone position using microwave imaging: A feasibility study

Vignesh Radhakrishnan*, Martin Paul Robinson, Peter John Ellison, Samadhan Bhaulal Patil, Adar Pelah

*Corresponding author for this work

Research output: Contribution to conferencePaperpeer-review


Background: Errors in bone position estimation, due to movement of underlying soft tissues in clinical skin-mounted marker-based systems, are the most critical source of error in movement analysis. Fluoroscopy is used to ameliorate these errors, but its adoption is limited due to high costs and its highly ionising nature (1,2). Microwave imaging, a low-cost, non-ionising imaging modality, whose applicability to breast tumour detection has been widely researched (3), has been increasingly used in studies for detecting strokes, brain-haemorrhages, fractures and in determining the variation in bone properties due to osteoporosis and osteopenia (4,5).
In this study we analyse the feasibility of detecting bones using microwave imaging.
Methods: Simulations were implemented using the finite-difference time-domain solver in Sim4Life (6) (Figure 1). Seven wearable antennas (7) were placed around the thigh of a virtual population model, Duke. Three multiport simulations were performed with the dielectric properties of the right femur varied to match that of bone, muscle and air. Scattering parameters were calculated in Sim4Life and the results were plotted.
Results: Variation in magnitude, resonant frequency and phase were observed in the scattering parameters when the bone dielectric properties were switched between bone, muscle and air (Figure 2). Diametrically opposite antennas show increased variation. Electric field penetration in to the thigh is shown in Figure 3.
Discussion and Conclusion: Variation in scattering parameters has been used to indicate the presence of fracture, tumours and to show variation between osteoporotic and normal bones (4,5). Our results show a notable difference in scattering parameters when the bone dielectric properties are varied, indicating the presence of the bone. The variation in scattering parameters, and penetration of electric field into the thigh, is dependent on the location of the antenna, which underscores its morphological dependence. We hypothesise this information can be used to determine the position of the bone relative to the antenna attached to the subject’s skin. Here we have shown that microwave imaging using wearable antennas, without any coupling medium, can be used to detect the position of the bone, which can aid in accurate movement analysis.
Key Words: Microwave imaging, movement analysis, soft tissue, antennas, Sim4Life
Key References:
1. Leardini,A. et al. Gait Posture 21, 212–225 (2005). 2. Fiorentino, N. M. et al.. Gait Posture 55, 184–190 (2017). 3. Elahi MA, et al. Sensors 18, (2018). 4. Islam MS, et al. Sci. Rep. 12, 8895 (2022). 5. Makarov SN, et al Sci. Rep. 10, 3540 (2020). 6. ZMT Zurich Med Tech AG, Zurich, Switzerland. 7. Gallucci, S. et al. Int. J. Environ. Res. Public Health 19, (2022).
Original languageEnglish
Number of pages1
Publication statusPublished - 28 Feb 2023
EventIPEM Science, Technology and Engineering Forum 2023 - University of Strathclyde, Technology & Innovation Centre, Glasgow, United Kingdom
Duration: 28 Feb 20231 Mar 2023


ConferenceIPEM Science, Technology and Engineering Forum 2023
Abbreviated titleIPEM STEF
Country/TerritoryUnited Kingdom
Internet address


  • Microwave imaging
  • movement analysis
  • soft tissue
  • antennas
  • Sim4Life

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