Numerical solving of inverse non-Fourier bioheat problem for use in dynamic thermographyHorvat, Ivan Dominik (Avtor) Iljaž, Jurij (Mentor) numerical modelingnon-Fourier bioheat transferboundary element methodinverse problem solvingoptimizationInfrared thermography is a non-invasive technique applied across industrial, environmental, and medical fields for detecting and interpreting surface temperature distributions. In medical diagnostics, dynamic infrared thermography can reveal underlying physiological processes such as altered metabolism and angiogenesis through subtle thermal anomalies, particularly in the use for early skin cancer diagnosis. However, conventional diagnostic methods remain subjective and prone to false alarms, while standard Fourier-based bioheat models fail to capture rapid transient thermal behavior in heterogeneous tissues. This doctoral research addresses these limitations by developing a numerical solver for solving direct and inverse problems, based on the dual-phase-lag non-Fourier bioheat model and a subdomain boundary element method, enabling accurate simulation of multilayer skin structures under dynamic thermal conditions. The direct problem analysis demonstrated that incorporating non-Fourier effects enhances the thermal contrast between healthy and tumor-affected tissues. A hybrid Levenberg-Marquardt optimization algorithm was implemented for solving the inverse problem, allowing the estimation of diagnostically critical parameters such as tumor diameter, thickness, blood perfusion rate, and thermal relaxation time from noisy surface temperature measurements. Results showed that tumor diameter and thermal relaxation time were the most stable and reliably estimated parameters, while blood perfusion rate and tumor thickness were highly sensitive to noise, especially for deeper lesions and increased model uncertainties. Furthermore, the study revealed that absolute temperature measurements provided more accurate inverse results than relative thermal contrast, and that non-Fourier effects notably delayed tumor thermal response, an insight crucial for optimizing dynamic thermography protocols. These contributions advance the understanding of bioheat transfer in living tissues, improve the accuracy and robustness of non-invasive diagnostic techniques, and lay the foundations for future clinical applications of dynamic infrared thermography.[I. D. Horvat]20252025-04-25 09:03:38Doktorsko delo/naloga92618sl