Prindeze, Nicholas J Mann, Yvette V L Feric, Tony G Currie, Timothy R Carney, Bonnie C Moffatt, Lauren T Shupp, Jeffrey W

Heat transfer analysis and resolution quantification of active dynamic thermography through human skin. - 2018

OBJECTIVES: Active dynamic thermography (ADT) is a non-contact imaging technique that characterizes non-homogeneities in thermal conductance through objects as a response to applied energy stimulus. The aim of this study was to (i) develop a heat transfer model to define the relationship between thermal stimulation and resolution and (ii) empirically quantify the resolution an ADT imaging system can detect through a range of depths of human skin. MATERIALS AND METHODS: A heat transfer model was developed to describe a thermally non-conductive object below a sheet of skin. The size and depth of the object were varied to simulate wound conditions, while the intensity and duration of thermal stimulation were varied to define stimulation parameters. The model was solved by numerical analysis. For ex vivo experimentation, freshly excised human pannus tissue was cut into sheets of thickness 2.54-6.35x10-4 m (0.010-0.025vinches) for a total of 48 grafts from 12 patients. Grafts were placed over a 3D printed resolution target with objects ranging from 0.445-0.125LP/mm. Stimulation from a 300W halogen lamp array was applied for 0.5-14seconds for a total of 480 experiments. RESULTS: ADT resolved a peak of 0.428+/-0.025LP/mm for 2.54x10-4 m (0.010 inches) skin thickness, 0.384+/-0.030LP/mm for 3.81x10-4 m (0.015 inches), 0.325+/-0.042LP/mm for 5.08x10-4 m (0.020 inches) and 0.249+/-0.057LP/mm for 6.35x10-4 m (0.025 inches) skin thickness. Additionally, it was determined that the ideal duration of stimulation energy with a 300W stimulation system was 4 seconds for 2.54x10-4 m, 6 seconds for 3.81x10-4 m, 8 seconds for 5.08x10-4 m, and 14 seconds for 6.35x10-4 m skin thickness. CONCLUSIONS: This study has characterized the correlation between thermal stimulus input and resolvable object size and depth for ADT. Through ex vivo experimentation it has also quantified the functional imaging depth to below the sub-cutis, beyond that of conventional imaging techniques. Lasers Surg. Med. (c) 2018 Wiley Periodicals, Inc. Copyright (c) 2018 Wiley Periodicals, Inc.



10.1002/lsm.22790 [doi]


MedStar Health Research Institute

Firefighters' Burn and Surgical Research Laboratory

Journal Article

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