title: Validation of a Hybrid Microwave-Optical Monitor to Investigate Thermal Provocation in the Microvasculature.
abstract: We have previously developed a hybrid microwave-optical system to monitor microvascular changes in response to thermal provocation in muscle. The hybrid probe is capable of inducing deep heat from the skin surface using mild microwaves (1-3 W) and raises the tissue temperature by a few degrees Celsius. This causes vasodilation and the subsequent increase in blood volume is detected by the hybrid probe using near infrared spectroscopy. The hybrid probe is also equipped with a skin cooling system which lowers the skin temperature while allowing microwaves to warm up deeper tissues. The hybrid system can be used to assess the condition of the vasculature in response to thermal stimulation. In this validation study, thermal imaging has been used to assess the temperature distribution on the surface of phantoms and human calf, following microwave warming. The results show that the hybrid system is capable of changing the skin temperature with a combination of microwave warming and skin cooling. It can also detect thermal responses in terms of changes of oxy/deoxy-hemoglobin concentrations.
authors.affiliation: Department of Electronic and Electrical Engineering, University College London, London, UK.
authors.forename: Allann
authors.initials: A
authors.lastname: Al-Armaghany
authors.affiliation: Department of Electronic and Electrical Engineering, University College London, London, UK.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Tong
authors.affiliation: Neurocritical Care, University College London Hospitals, Queen Square, London, UK.
authors.forename: David
authors.initials: D
authors.lastname: Highton
authors.affiliation: Department of Medical Physics and Biomedical Engineering, University College London, London, UK. t.leung@ucl.ac.uk.
authors.forename: Terence S
authors.initials: TS
authors.lastname: Leung
mesh_terms: D006801:Humans; D055806:Microvessels / Q000502:physiology*; D008872:Microwaves; D012881:Skin Temperature; D014664:Vasodilation
keywords: Microwave applicator; Muscle; Near infrared spectroscopy; Thermoregulation; Vasodilation