Interest in using optical methods in the development of noninvasive clinicaldiagnostic and therapeutic techniques for brain diseases has widely increased due to theirsimplicity, safety, and affordability. The main limitations of light-based techniques usedfor brain theranostics are the strong light scattering in the scalp and skull, which causedecrease of spatial resolution, low contrast, and small penetration depth. To address thischallenge, our group has previously introduced a transparent nanocrystallineyttria-stabilized-zirconia (nc-YSZ) cranial implant material which implant possesses themechanical strength and biocompatibility that are prerequisites for a clinically-viablepermanent cranial implant for patients.

This implant possesses the mechanical strength and biocompatibility that areprerequisites for a clinically-viable permanent cranial implant for patients. A potentialbenefit of this optical window is an improvement of light-based therapeutic techniquesthat rely on sufficient light penetration to a target embedded in tissue such asphotobiomodulation, photodynamic therapy, and optogenetics. Another application of thisoptical window is noninvasive visualization of brain blood vessels, hematomas, and smallpathologic structures (including cancerous growth) with high resolution. This isimportant for diagnosis and treatment of many diseases such as tumors of the brain,vascular pathologies, and so forth. In this dissertation, I investigated (1) characteristicsand durability of transparent nc-YSZ implants; (2) feasibility of chronic brain imagingthrough the implant; (3) multimodal imaging across the implant to generate anarteriovenous vascular map; (4) through-scalp VIS-NIR light delivery and microvascularimaging.