Numerical analysis of the optical fluence rate at the scalp for noninvasive brain tumor detection

Abstract

The present study provides a noninvasive, safe approach for brain tumor detection by numerically analyzing the optical fluence rate at the scalp. The proposed numerical investigation demonstrates the application of different laser wavelengths for identifying different types and volumes of brain tumors (glioma “grade II astrocytoma” and meningioma). The proposed method analyzes the spatial fluence rate distribution over the surface of the head after probing it with different infrared laser wavelengths (1000 and 1100 nm) to distinguish between normal and brain tumors. A multilayer head model is created with COMSOL Multiphysics 5.4 simulation software, where the Helmholtz equation is solved using a finite element method to visualize the optical fluence rate at the model’s surface. The resultant fluence rate images show different features between normal brain and brain tumors, especially at 1000 nm.

Alzheimer's disease progression detection based on optical fluence rate measurements using alternative laser wavelengths

“…The optical parameters of AD are mentioned in the literature without clarifying the AD stage, which depends on the entire brain matter volume 41,42 . The optical parameters of the scalp layer are used for Caucasian skin 43–45 . The diffusion equation (Equation 1) states the relation between the propagated diffuse light through the biological tissue and the photon intensity of the tissue's surface area as the fluence rate of the simulated tissue 43 …”

“…41,42 The optical parameters of the scalp layer are used for Caucasian skin. [43][44][45] The diffusion equation (Equation 1) states the relation between the propagated diffuse light through the biological tissue and the photon intensity of the tissue's surface area as the fluence rate of the simulated tissue. 43 1 C…”

“…Dx, Dy, and Dz are the diffusion coefficients (function of scattering coefficient, absorption coefficient, and anisotropy (g)) in the x, y, and z-direction, respectively (Equation 2). 43…”

“…In our simulation, the anisotropy factor (g) = 0.89 is assumed for all tissue layers. 43 F I G U R E 2 The laser source is located in the middle front of the forehead, and the measurements use (A) an array of the photodetectors and (B) the matrix of photodetectors.…”

Early cancer detection using the fluorescent Ashwagandha chitosan nanoparticles combined with near-infrared light diffusion characterization: in vitro study

“…Recently, ultra-small nanoparticles conjugated to a melanoma biomarker are utilized as a contrast agent in optical coherence tomography (OCT), showing improvement in differentiating melanoma cells from nonmelanoma cell differentiation in vitro [36]. Diffuse optical tomography is a safe, non-invasive technology that employs a laser in the red-NIR region (600 to 900 nm) to probe biological tissues/organs and characterize their absorption and scattering properties [37][38][39][40]. These properties control the light propagation in the observed tissues and differ according to the applied wavelength [41][42][43].…”