Optical and thermal characterization of ex vivo porcine pancreatic tissue under controlled temperature variation

Minimally invasive photothermal approaches for pancreatic cancer require accurate knowledge of pancreatic tissue properties to optimize light delivery, predict heat diffusion, and prevent off-target damage. This work presents a combined optical–thermal characterization of ex vivo porcine pancreatic tissue under controlled heating, providing temperature-dependent parameters for biophysical modeling and treatment planning. Broadband time-domain diffuse optical spectroscopy over a wide spectral range (650–1100 nm) was employed to retrieve absorption (𝜇𝑎) and reduced scattering (𝜇's) coefficients during stepwise thermal treatment at 14 °C, 42 °C, and 63 °C. In parallel, thermal conductivity, thermal diffusivity, and volumetric heat capacity were measured with the transient hot-wire technique in the 22–45 °C relevant range. Thermal exposure induced noticeable spectral modifications in 𝜇𝑎, in particular, the rise of two peaks at wavelengths of 760 nm and 830 nm at temperatures of 63 °C, consistent with thermally driven denaturation of deoxyhemoglobin. In contrast, 𝜇's spectra exhibited minimal changes across the three temperature conditions. Furthermore, in the 22–45 °C interval, pancreatic thermal properties remained nearly constant, while progressive softening and semi-liquid transition above this range limited reliable thermal probing. The reported temperature-dependent optical and thermal behavior of pancreatic tissue provides experimentally grounded input for bioheat-transfer simulations and light-transport models, supporting the design, optimization, and safety assessment of laser-based hyperthermal and ablative strategies in pancreatic applications.