Multi-layered tissue head phantoms for noninvasive optical diagnostics

Extensive research in the area of optical sensing for medical diagnostics requires development of tissue phantoms with opt ical properties similar to those of living human tissues.Development and improvement of in vivo optical measurement systems requires the 1use of stable tissue phantoms with known characteristics,which are mainly used for calibration of such systems and testing their performance over time.Optical and mechanical properties of phantoms depend on their purpose.Nevertheless,they must accurately simulate specific tssues they are supposed to mimic.Many tsues and organs including head possess a multi-layered structure,with specifie optical properties of each layer.However,such a structure is not always addressed in the present-day phantoms.In this paper,we focus on the development of a plain-parallel multi-layered phantom with optical properties(reduced scattering oofficientμ'and absorption cofficientμa)corresponding to the human head layers,such as skin,skul,and gray and white matter of the brain tissue.The phantom is intended for use in noninvasive diffuse near-infrared spectroscopy(NIRS)of humnan brain.Optical parameters of the fabricated phantoms are reconstructed using spectrophotometry and inverse adding-doubling calculation method.The results show that polyinyl chloride plastisol(PVCP)and zinc oxide(ZnO)nanoparticles are suitable materials for fabrication of tissue mimicking phantoms with controlled scattering properties.Good matching was found between optical properties of phantoms and the corresponding values found in the literature.