Tissue-Mimicking Phantoms for Investigating Laser Ablation and Thermotherapy

Abstract

Laser ablation is widely used in modern medicine for the treatment of liver, kidney, prostate, and bone tumors, as well as other pathological conditions. The efficacy and safety of the procedure are largely determined by the laser irradiation parameters, making the preliminary optimization of treatment protocols an essential task. The use of biological tissues for such studies is associated with several limitations, including structural heterogeneity, variability of optical properties, difficulties in storage, and ethical concerns related to the use of animal models. Consequently, tissue-mimicking phantoms have been extensively developed to enable reproducible investigations of laser–tissue interactions under controlled experimental conditions. Despite the wide variety of existing phantoms based on agarose, gelatin, polyacrylamide, and other materials, most of them fail to simultaneously reproduce the optical, mechanical, and thermophysical properties of biological tissues or exhibit limited thermal stability. In this study, we present two types of tissue-mimicking phantoms designed to model laser–tissue interactions at a wavelength of 1064 nm. For the experimental evaluation, laser exposure was performed using a pulsed Nd:YAG laser (λ = 1064 nm, pulse duration 220 μs) with optical fiber delivery. To simulate bone tissue, synthetic opals composed of monodisperse SiO₂ particles were fabricated using the Stöber method. Due to the highly porous structure of the opal matrices and their infiltration with CuSO₄ solutions, the attenuation coefficient in the near-infrared spectral region could be adjusted, enabling the optical properties of bone tissue at 1064 nm to be reproduced. Laser exposure experiments demonstrated a similar pattern of thermal damage zone formation in the developed phantoms and ex vivo bone tissue samples.To simulate liver tissue, phantoms based on alginate hydrogel supplemented with ovalbumin and copper sulfate were developed. The fabricated phantoms reproduced the optical properties of liver tissue over a wavelength range including 1064 nm and generated coagulation and ablation zones with geometrical characteristics comparable to those observed in ex vivo liver tissue samples.The obtained results demonstrate that the developed bone tissue phantoms based on opal matrices and liver phantoms based on alginate hydrogel successfully reproduce the key characteristics of biological tissues under laser irradiation. The ability to tailor their optical properties makes these phantom systems promising platforms for investigating laser ablation processes, optimizing laser irradiation parameters, and evaluating medical laser systems.
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Speaker

Mirzaeva Sophia
Prokhorov General Physics Institute of the Russian Academy of Sciences
Russia

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