Effects of Skin Pores on Photon Propagation in Optical Brain Imaging Systems
7th International Conference on Applications of Optics and Photonics, Lisbon, Portekiz, 7 - 10 Temmuz 2026, cilt.10, sa.1, ss.24, (Özet Bildiri)
- Yayın Türü: Bildiri / Özet Bildiri
- Cilt numarası: 10
- Doi Numarası: 10.34629/ipl.isel.i-etc.108
- Basıldığı Şehir: Lisbon
- Basıldığı Ülke: Portekiz
- Sayfa Sayıları: ss.24
- Açık Arşiv Koleksiyonu: AVESİS Açık Erişim Koleksiyonu
- Acıbadem Mehmet Ali Aydınlar Üniversitesi Adresli: Evet
Özet
In optical brain imaging systems, near-infrared photons emitted by light emitting diodes (LEDs) must penetrate scalp and other tissue layers to reach the brain, and even a single skin pore at the scalp-LED interface can alter optical power, yet its effect is rarely quantified. In this study, we use finite element method (FEM) simulations to examine photon propagation in a model including a single pore of 500 μm diameter and 50 μm depth within the scalp. The pore was systematically displaced along the scalp-LED boundary in 0.1 mm steps for 30 positions to investigate how its location affects light propagation, and 5000 photons at 735 nm wavelength with a 70 degree half-angle were emitted, representing specifications of typical LED sources used in optical brain imaging systems. A layered human head model consisting of scalp, skull, cerebrospinal fluid (CSF), and brain was constructed, and realistic refractive index values were assigned to each tissue layer. To assess the effect of the pore on light propagation, photon power reduction was tracked at each tissue layer interface, and pore position versus optical power graphs were plotted for all interfaces. Results show that optical power at the scalp-skull interface varied within the 89.65 to 87.77% range as the skin pore radial position changed between −1.5 and +1.5 mm, with deviations across positions. Corresponding variations were observed at deeper interfaces, with skull-CSF interface optical power ranging from 80.76 to 79.69% and CSF-brain interface optical power ranging from 68.40 to 63.73% over the same skin pore radial position range. While optical power at the scalp-skull and skull-CSF interfaces decreases as the pore approaches the LED center, an opposite trend is observed at the CSF-brain interface, where optical power increases with central pore alignment. This inversion suggests that centrally located pores disrupt near-field photon transport at superficial layers while redistributing photon trajectories toward more forward-directed paths that enhance deeper penetration. These findings highlight a source of position-dependent variability in optical brain imaging systems that can directly impact system signal-to-noise ratio (SNR) and effective depth sensitivity. Improving LED-scalp coupling, such as through controlled LED compression against the scalp, may reduce pore-induced fluctuations by effectively suppressing pore-related air gaps and improve measurement robustness at tissue layers.