Developing optical mimicking phantoms of the head tissues – a new approach for transcranial photobiomodulation research

• Autor(es): Fernandes, Filipa ; Silva, Filipe S. ; Sousa,Nuno ; Catarino, Susana Oliveira ; Carvalho, Óscar Samuel Novais
• Data: 2024
• Identificador Persistente: https://hdl.handle.net/1822/93680
• Origem: RepositóriUM - Universidade do Minho
• Tipo de Documento: Outro
• Idioma: Inglês
• Contribuidor(es): Universidade do Minho

Descrição

Transcranial photobiomodulation (tPBM) has gained relevance in the recent decade, due to positive results in clinical trials for several neurological pathologies (e.g., stroke, traumatic brain injury, dementia related diseased). Nonetheless, the uncertainty around the ideal light parameters causes some resistance in the incorporation of this therapy into mainstream practice [1]. To establish optimal stimulation parameters, it is important to first understand how light interacts with the relevant tissue, but using biological tissues for this research involves several ethical considerations and may be wasteful. Thus, to provide better alternatives for tPBM research, optical mimicking phantoms were developed using low-cost and sustainable materials. Agarose was used as matrix to which titanium dioxide (TiO2); India ink; organometallic compounds; and laser-ablated gold and zinc were added. The transmittance and reflectance spectra of the phantoms and porcine tissues (i.e., skin, muscle, cranium, brain, and cerebellum) were characterized using an integrating sphere, and later compared to find similarities between the two. Overall, it was possible to establish similarities between the porcine tissues’ and the phantoms’ optical properties, but it was noted that finding a phantom that could replicate both the reflectance and absorbance spectra of a given tissue might be a difficult task. Further studies are required to study different concentrations and combinations of the materials to more closely mimic the optical properties of the biological tissues.