{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,19]],"date-time":"2026-10-19T17:37:22Z","timestamp":1792431442702,"version":"4.5.0"},"reference-count":50,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2022,10,25]],"date-time":"2022-10-25T00:00:00Z","timestamp":1666656000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diagnostics"],"abstract":"<jats:p>Accurate knowledge about the dielectric properties of biological tissues in the microwave frequency range may lead to advancement of biomedical applications based on microwave technology. However, the published data are very scarce, especially for human brain tissues. The aim of this work was to measure and report the complex permittivity of brain white matter, grey matter and cerebellum. Complex permittivity was measured on human, bovine and porcine brain tissues in the microwave frequency range from 0.5 to 18 GHz using an open-ended coaxial probe. The results present a valuable addition to the available data on the brain tissue complex permittivity. Some noticeable variations between the results lead to several conclusions. Complex permittivity variation within the same tissue type of the individual species was comparable to interspecies variation. The difference was prominent between human brains obtained from autopsies, while bovine brains obtained from healthy animals showed very similar complex permittivity. We hypothesize that the difference might have been caused by the basic pathologies of the patients, where the associated therapies could have affected the brain water content. We also examined the effect of excised tissue degradation on its complex permittivity over the course of three days, and the results suggest the gradual dehydration of the samples.<\/jats:p>","DOI":"10.3390\/diagnostics12112580","type":"journal-article","created":{"date-parts":[[2022,10,25]],"date-time":"2022-10-25T12:29:45Z","timestamp":1666700985000},"page":"2580","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["Complex Permittivity of Ex-Vivo Human, Bovine and Porcine Brain Tissues in the Microwave Frequency Range"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9442-9347","authenticated-orcid":false,"given":"An\u0111ela","family":"Matkovi\u0107","sequence":"first","affiliation":[{"name":"FESB, University of Split, HR-21000 Split, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anton","family":"Kordi\u0107","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, University Hospital Centre Zagreb, HR-10000 Zagreb, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Antonia","family":"Jakov\u010devi\u0107","sequence":"additional","affiliation":[{"name":"Department of Pathology and Cytology, University Hospital Centre Zagreb, HR-10000 Zagreb, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7941-1977","authenticated-orcid":false,"given":"Antonio","family":"\u0160aroli\u0107","sequence":"additional","affiliation":[{"name":"FESB, University of Split, HR-21000 Split, Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,10,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Crocco, L., Karanasiou, I., James, M.L., and Concei\u00e7\u00e3o, R.C. (2018). Emerging Electromagnetic Technologies for Brain Diseases Diagnostics, Monitoring and Therapy, Springer International Publishing.","DOI":"10.1007\/978-3-319-75007-1"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"4060","DOI":"10.1109\/TMI.2020.3011359","article-title":"Non-Invasive RF Technique for Detecting Different Stages of Alzheimer\u2019s Disease and Imaging Beta-Amyloid Plaques and Tau Tangles in the Brain","volume":"39","author":"Saied","year":"2020","journal-title":"IEEE Trans. Med. Imaging"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"2806","DOI":"10.1109\/TBME.2014.2330554","article-title":"Microwave-Based Stroke Diagnosis Making Global Prehospital Thrombolytic Treatment Possible","volume":"61","author":"Persson","year":"2014","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"2176","DOI":"10.1089\/neu.2016.4869","article-title":"Clinical Evaluation of a Microwave-Based Device for Detection of Traumatic Intracranial Hemorrhage","volume":"34","author":"Ljungqvist","year":"2017","journal-title":"J. Neurotrauma"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"El rube\u2019, I., Heatley, D., and Abdel-Maguid, M. (2021). Detecting a Stroke-Affected Region in the Brain by Scanning with Low-Intensity Electromagnetic Waves in the Radio Frequency\/Microwave Band. Healthcare, 9.","DOI":"10.3390\/healthcare9091170"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1335","DOI":"10.1007\/s00068-021-01671-7","article-title":"Microwave scan and brain biomarkers to rule out intracranial hemorrhage: Study protocol of a planned prospective study (MBI01)","volume":"48","author":"Vedin","year":"2022","journal-title":"Eur. J. Trauma Emerg. Surg."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"6093","DOI":"10.1088\/0031-9155\/52\/20\/002","article-title":"A large-scale study of the ultrawideband microwave dielectric properties of normal, benign and malignant breast tissues obtained from cancer surgeries","volume":"52","author":"Lazebnik","year":"2007","journal-title":"Phys. Med. Biol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"301","DOI":"10.1586\/erd.13.5","article-title":"MarginProbe \u00ae: Intraoperative margin assessment during breast conserving surgery by using radiofrequency spectroscopy","volume":"10","author":"Thill","year":"2013","journal-title":"Expert Rev. Med. Devices"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"2743","DOI":"10.1088\/0031-9155\/56\/9\/007","article-title":"Microwave beamforming for non-invasive patient-specific hyperthermia treatment of pediatric brain cancer","volume":"56","author":"Burfeindt","year":"2011","journal-title":"Phys. Med. Biol."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Schooneveldt, G., Dob\u0161\u00ed\u010dek Trefn\u00e1, H., Persson, M., de Reijke, T.M., Blomgren, K., Kok, H.P., and Crezee, H. (2019). Hyperthermia Treatment Planning Including Convective Flow in Cerebrospinal Fluid for Brain Tumour Hyperthermia Treatment Using a Novel Dedicated Paediatric Brain Applicator. Cancers, 11.","DOI":"10.3390\/cancers11081183"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"704","DOI":"10.1080\/02656736.2017.1383517","article-title":"Hyperthermia treatment planning guided applicator selection for sub-superficial head and neck tumors heating","volume":"34","author":"Drizdal","year":"2018","journal-title":"Int. J. Hyperthermia"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"9685476","DOI":"10.1155\/2019\/9685476","article-title":"Role of Simulations in the Treatment Planning of Radiofrequency Hyperthermia Therapy in Clinics","volume":"2019","author":"Prasad","year":"2019","journal-title":"J. Oncol."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Datta, N.R., Jain, B.M., Mathi, Z., Datta, S., Johari, S., Singh, A.R., Kalbande, P., Kale, P., Shivkumar, V., and Bodis, S. (2022). Hyperthermia: A Potential Game-Changer in the Management of Cancers in Low-Middle-Income Group Countries. Cancers, 14.","DOI":"10.3390\/cancers14020315"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Kroesen, M., van Holthe, N., Sumser, K., Chitu, D., Vernhout, R., Verduijn, G., Franckena, M., Hardillo, J., van Rhoon, G., and Paulides, M. (2021). Feasibility, SAR Distribution, and Clinical Outcome upon Reirradiation and Deep Hyperthermia Using the Hypercollar3D in Head and Neck Cancer Patients. Cancers, 13.","DOI":"10.3390\/cancers13236149"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"17","DOI":"10.4103\/sni.sni_361_18","article-title":"Preliminary experience in the management of brain and skull-base tumors with microwave ablation; feasibility guided by ultrasound, report from 23 cases","volume":"10","year":"2019","journal-title":"Surg. Neurol. Int."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Redr, J., Pokorny, T., Drizdal, T., Fiser, O., Brunat, M., Vrba, J., and Vrba, D. (2022). Microwave Hyperthermia of Brain Tumors: A 2D Assessment Parametric Numerical Study. Sensors, 22.","DOI":"10.3390\/s22166115"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"(2020). International Commission on Non-Ionizing Radiation Protection (ICNIRP) Guidelines for Limiting Exposure to Electromagnetic Fields (100 kHz to 300 GHz). Health Phys., 118, 483\u2013524.","DOI":"10.1097\/HP.0000000000001210"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"5287","DOI":"10.1088\/0031-9155\/59\/18\/5287","article-title":"Development of a new generation of high-resolution anatomical models for medical device evaluation: The Virtual Population 3.0","volume":"59","author":"Gosselin","year":"2014","journal-title":"Phys. Med. Biol."},{"key":"ref_19","unstructured":"ZMT Zurich MedTech, AG (2022, August 18). Sim4Life. Available online: https:\/\/zmt.swiss\/sim4life\/."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Gabriel, C. (1996). Compilation of the Dielectric Properties of Body Tissues at RF and Microwave Frequencies, Occupational and Environmental Health Directorate, Radiofrequency Radiation Division, Brooks Air Force Base.","DOI":"10.21236\/ADA303903"},{"key":"ref_21","unstructured":"Hasgall, P.A., Di Gennaro, F., Baumgartner, C., Neufeld, E., Lloyd, B., Gosselin, M.C., Payne, D., Klingenb\u00f6ck, A., and Kuster, N. (2022, August 21). IT\u2019IS Database for Thermal and Electromagnetic Parameters of Biological Tissues, Version 4.1. Available online: itis.swiss\/database."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"341","DOI":"10.1063\/1.1750906","article-title":"Dispersion and Absorption in Dielectrics I. Alternating Current Characteristics","volume":"9","author":"Cole","year":"1941","journal-title":"J. Chem. Phys."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"\u0160aroli\u0107, A., and Matkovi\u0107, A. (2022). Dielectric Permittivity Measurement Using Open-Ended Coaxial Probe\u2014Modeling and Simulation Based on the Simple Capacitive-Load Model. Sensors, 22.","DOI":"10.3390\/s22166024"},{"key":"ref_24","unstructured":"Keysight Technologies (2018). Keysight N1501A Dielectric Probe Kit 10 MHz to 50 GHz\u2014Technical Overview, Keysight Technologies."},{"key":"ref_25","unstructured":"Keysight Technologies (2021). Field Fox Handheld Analyzers\u2014Technical Overview 2021, Keysight Technologies."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"La Gioia, A., Porter, E., Merunka, I., Shahzad, A., Salahuddin, S., Jones, M., and O\u2019Halloran, M. (2018). Open-Ended Coaxial Probe Technique for Dielectric Measurement of Biological Tissues: Challenges and Common Practices. Diagnostics, 8.","DOI":"10.3390\/diagnostics8020040"},{"key":"ref_27","unstructured":"Keysight Technologies (2021). N1500A Materials Measurement Suite\u2014Technical Overview 2021, Keysight Technologies."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"423","DOI":"10.1002\/bem.10123","article-title":"Dielectric properties of human brain tissue measured less than 10 h postmortem at frequencies from 800 to 2450 MHz","volume":"24","author":"Schmid","year":"2003","journal-title":"Bioelectromagnetics"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"4711","DOI":"10.1088\/0031-9155\/50\/19\/019","article-title":"Age dependence of dielectric properties of bovine brain and ocular tissues in the frequency range of 400 MHz to 18 GHz","volume":"50","author":"Schmid","year":"2005","journal-title":"Phys. Med. Biol."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"2229","DOI":"10.1088\/0031-9155\/52\/8\/013","article-title":"Dielectric properties of porcine cerebrospinal tissues at microwave frequencies: In vivo, in vitro and systematic variation with age","volume":"52","author":"Peyman","year":"2007","journal-title":"Phys. Med. Biol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"621","DOI":"10.1088\/0031-9155\/30\/7\/001","article-title":"Dielectric properties of mammalian brain tissue between 1 and 18 GHz","volume":"30","author":"Steel","year":"1985","journal-title":"Phys. Med. Biol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1133","DOI":"10.1088\/0031-9155\/29\/9\/009","article-title":"Variation with age of the dielectric properties of mouse brain cerebrum","volume":"29","author":"Thurai","year":"1984","journal-title":"Phys. Med. Biol."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"421","DOI":"10.1002\/bem.2250030405","article-title":"In vivo and in vitro dielectric properties of animal tissues at radio frequencies","volume":"3","author":"Kraszewski","year":"1982","journal-title":"Bioelectromagnetics"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"38","DOI":"10.1109\/TMTT.1986.1133278","article-title":"In Situ Permittivity of Canine Brain: Regional Variations and Postmortem Changes","volume":"34","author":"Burdette","year":"1986","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"1424","DOI":"10.1109\/TMTT.1987.1133870","article-title":"Measurement of the Dielectric Properties of Biological Substances Using an Improved Open-Ended Coaxial Line Resonator Method","volume":"35","author":"Xu","year":"1987","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1002\/bem.2250020202","article-title":"Dielectric properties of animal tissues in vivo at frequencies 10 MHz\u20131 GHz","volume":"2","author":"Stuchly","year":"1981","journal-title":"Bioelectromagnetics"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"1177","DOI":"10.1088\/0031-9155\/24\/6\/008","article-title":"Dielectric properties of brain tissue between 0.01 and 10 GHz","volume":"24","author":"Foster","year":"1979","journal-title":"Phys. Med. Biol."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"467","DOI":"10.1615\/CritRevBiomedEng.2015012486","article-title":"Review of Temperature Dependence of Thermal Properties, Dielectric Properties, and Perfusion of Biological Tissues at Hyperthermic and Ablation Temperatures","volume":"42","author":"Rossmann","year":"2014","journal-title":"Crit. Rev. Biomed. Eng."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"1094","DOI":"10.1002\/mrm.26193","article-title":"Electrical conductivity and permittivity maps of brain tissues derived from water content based on T1-weighted acquisition","volume":"77","author":"Michel","year":"2017","journal-title":"Magn. Reson. Med."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"474","DOI":"10.1002\/bem.22054","article-title":"Closed-form equation to estimate the dielectric properties of biological tissues as a function of age: Dielectric Properties of Biological Tissues","volume":"38","author":"Mohammed","year":"2017","journal-title":"Bioelectromagnetics"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"117040","DOI":"10.1016\/j.neuroimage.2020.117040","article-title":"The association of white matter free water with cognition in older adults","volume":"219","author":"Gullett","year":"2020","journal-title":"NeuroImage"},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Jones, S.B., Sheng, W., and Or, D. (2022). Dielectric Measurement of Agricultural Grain Moisture\u2014Theory and Applications. Sensors, 22.","DOI":"10.3390\/s22062083"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"9095","DOI":"10.1038\/s41598-020-66022-9","article-title":"Water is a biomarker of changes in the cellular environment in live animals","volume":"10","author":"Siwach","year":"2020","journal-title":"Sci. Rep."},{"key":"ref_44","first-page":"CD000567","article-title":"Colloids versus crystalloids for fluid resuscitation in critically ill people","volume":"8","author":"Lewis","year":"2018","journal-title":"Cochrane Database Syst. Rev."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1172\/JCI200422353","article-title":"Acute renal failure: Definitions, diagnosis, pathogenesis, and therapy","volume":"114","author":"Schrier","year":"2004","journal-title":"J. Clin. Investig."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"349","DOI":"10.1007\/s001010050841","article-title":"Medizin aktuell: Aktuelle Strategien Klinischer Ern\u00e4hrung II","volume":"49","author":"Haller","year":"2000","journal-title":"Anaesthesist"},{"key":"ref_47","unstructured":"DeSai, C., and Hays Shapshak, A. (2022). Cerebral Ischemia. StatPearls, StatPearls Publishing."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"568","DOI":"10.1097\/ACO.0000000000000764","article-title":"Hyperventilation in neurological patients: From physiology to outcome evidence","volume":"32","author":"Zhang","year":"2019","journal-title":"Curr. Opin. Anaesthesiol."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"7334","DOI":"10.1088\/0031-9155\/61\/20\/7334","article-title":"Dielectric characterization of healthy and malignant colon tissues in the 0.5\u201318 GHz frequency band","volume":"61","author":"Frasson","year":"2016","journal-title":"Phys. Med. Biol."},{"key":"ref_50","doi-asserted-by":"crossref","unstructured":"I\u0161tuk, N., Porter, E., O\u2019Loughlin, D., McDermott, B., Santorelli, A., Abedi, S., Joachimowicz, N., Roussel, H., and O\u2019Halloran, M. (2021). Dielectric Properties of Ovine Heart at Microwave Frequencies. Diagnostics, 11.","DOI":"10.3390\/diagnostics11030531"}],"container-title":["Diagnostics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2075-4418\/12\/11\/2580\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:02:07Z","timestamp":1760144527000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2075-4418\/12\/11\/2580"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,10,25]]},"references-count":50,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2022,11]]}},"alternative-id":["diagnostics12112580"],"URL":"https:\/\/doi.org\/10.3390\/diagnostics12112580","relation":{},"ISSN":["2075-4418"],"issn-type":[{"value":"2075-4418","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,10,25]]}}}