Optimization of Skin Cooling for Thermographic Imaging of Near-Surface Lesions

Abstract

With the dramatic advances in IR imaging technology, the IR imaging technique has the potential to become a promising non-contact in-vivo diagnostic tool for the early detection of melanoma [1] as well as other conditions in which the temperature of the body deviates from normal temperature. Active or dynamic IR (thermal) imaging, which involves introducing external cooling, can induce or enhance relevant thermal contrast observed on the skin surface, leading to temperature differences that can be accurately measured with a properly designed IR imaging system. When the skin surface is cooled down in active IR imaging, the variation in the thermal properties of the lesion located underneath the surface result in identifiable temperature differences from the surrounding healthy tissue in the recovery phase, and therefore the dynamic thermal response of the structure acquired using active imaging provides critical information to distinguish the diseased and healthy tissues. Regarding the effectiveness of the active IR imaging, in this study, the performance of varied cooling parameters, including cooling method, cooling temperature, cooling duration, and cooling depth are discussed. Toward the objective of minimizing the discomfort of patient, by evaluating the transient temperature difference in the recovery phase for varied cooling conditions, our goal is to find out the optimized cooling conditions, which can provide effective thermal response contrast in the recovery phase, while applying appropriate cooling temperature and duration to facilitate the clinical feasibility of this technique. The optimized cooling condition concluded from the simulation will be verified by the in-vivo dynamic thermal imaging experiments.