{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T05:07:17Z","timestamp":1787029637759,"version":"build-2736575974"},"reference-count":43,"publisher":"MDPI AG","issue":"21","license":[{"start":{"date-parts":[[2021,10,26]],"date-time":"2021-10-26T00:00:00Z","timestamp":1635206400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100002724","name":"American University of Sharjah","doi-asserted-by":"publisher","award":["FRG20-M-E96"],"award-info":[{"award-number":["FRG20-M-E96"]}],"id":[{"id":"10.13039\/501100002724","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>A major cause of bone mass loss worldwide is osteoporosis. X-ray is considered to be the gold-standard technique to diagnose this disease. However, there is currently a need for an alternative modality due to the ionizing radiations used in X-rays. In this vein, we conducted a numerical study herein to investigate the feasibility of using microwave tomography (MWT) to detect bone density variations that are correlated to variations in the complex relative permittivity within the reconstructed images. This study was performed using an in-house finite-element method contrast source inversion algorithm (FEM-CSI). Three anatomically-realistic human leg models based on magnetic resonance imaging reconstructions were created. Each model represents a leg with a distinct fat layer thickness; thus, the three models are for legs with thin, medium, and thick fat layers. In addition to using conventional matching media in the numerical study, the use of commercially available and cheap ultrasound gel was evaluated prior to bone image analysis. The inversion algorithm successfully localized bones in the thin and medium fat scenarios. In addition, bone volume variations were found to be inversely proportional to their relative permittivity in the reconstructed images with the root mean square error as low as 2.54. The observations found in this study suggest MWT as a promising bone imaging modality owing to its safe and non-ionizing radiations used in imaging objects with high quality.<\/jats:p>","DOI":"10.3390\/s21217078","type":"journal-article","created":{"date-parts":[[2021,10,26]],"date-time":"2021-10-26T23:54:33Z","timestamp":1635292473000},"page":"7078","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":20,"title":["Monitoring Bone Density Using Microwave Tomography of Human Legs: A Numerical Feasibility Study"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5248-6327","authenticated-orcid":false,"given":"Mohanad","family":"Alkhodari","sequence":"first","affiliation":[{"name":"Department of Electrical Engineering, American University of Sharjah, Sharjah P.O. Box 26666, United Arab Emirates"},{"name":"Department of Biomedical Engineering, Khalifa University, Abu Dhabi P.O. Box 127788, United Arab Emirates"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6655-5418","authenticated-orcid":false,"given":"Amer","family":"Zakaria","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, American University of Sharjah, Sharjah P.O. Box 26666, United Arab Emirates"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2253-994X","authenticated-orcid":false,"given":"Nasser","family":"Qaddoumi","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, American University of Sharjah, Sharjah P.O. Box 26666, United Arab Emirates"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,10,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"473","DOI":"10.1016\/j.jocd.2008.04.003","article-title":"National psteoporosis foundation 2008 clinician\u2019s guide to prevention and treatment of osteoporosis and the world health organization fracture risk assessment tool (FRAX): What they mean to the bone densitometrist and bone technologist","volume":"11","author":"Watts","year":"2008","journal-title":"J. Clin. Densitom."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"362","DOI":"10.1093\/ajcn\/79.3.362","article-title":"Vitamin D: Importance in the prevention of cancers, type 1 diabetes, heart disease, and osteoporosis","volume":"79","author":"Holick","year":"2004","journal-title":"Am. J. Clin. 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