Red and NIR light dosimetry in the human deep brain

Area of Science:

• Neuroscience
• Biomedical Engineering
• Photomedicine

Background:

• Parkinson's Disease (PD) is a neurodegenerative disorder.
• Photobiomodulation (PBM) is being investigated as a potential therapeutic approach for PD.
• Effective delivery of light to deep brain structures is crucial for PBM efficacy.

Purpose of the Study:

• To measure and model light propagation in deep brain tissues for transcranial and transsphenoidal illumination.
• To optimize optical parameters for enhanced light delivery to brain regions relevant to PD.
• To evaluate different illumination routes for improved PBM therapy in PD.

Main Methods:

• Monte Carlo simulations were used to model optical parameters of human brain tissue.
• Light propagation was measured in a cadaver head using transcranial and transsphenoidal illumination at 671 nm and 808 nm.
• A high-resolution voxel mesh of the skull was created to represent different tissue types.

Main Results:

• The 808 nm wavelength demonstrated better light delivery to deep brain tissues compared to 671 nm.
• Optimized optical parameters improved the accuracy of simulated light distribution.
• Ventricular illumination achieved a 20-fold higher efficiency for deep brain light delivery compared to transcranial methods.

Conclusions:

• Transcranial and transsphenoidal illumination are feasible for delivering light to deep brain tissues.
• Novel application routes, including the sphenoid sinus, combined with optimized parameters, enhance PBM efficiency for PD treatment.
• This research opens new therapeutic avenues for PD and other neurological conditions treatable with light therapy.