UMO-2011/03/D/ST6/03236

Head of the project: Norbert Żołek, PhD

The aim of the research related to the project is to develop methods and software for analyzing multiparameter probability distributions connected with distributions of times of flight of photons through given media. Estimation of the parameters of the distributions will allow for estimation of the optical properties of measured structures studied using near-infrared spectroscopy. Proper evaluation of absolute values of macroscopic optical properties and volume of penetration of structures of optically turbid medium is going to allow for wider usage of near-infrared spectroscopy measurements in medical diagnostics. Previous studies have demonstrated the possibility of broad use of non-invasive methods based on radiation of visible light and near-infrared for monitoring of cerebral oxygenation.

Unfortunately, difficulties in determining absolute values of the optical properties and volume of penetration of radiation in the measured structure prevented the wider use of these methods in routine clinical practice so far. Due to the high complexity of the propagation of light in tissue structures, complex theoretical models are needed to analyze the results of the measurements. One of the most accurate methods is method based on Monte Carlo simulations. Unfortunately, the method requires massive computing power to obtain statistically reliable results.

Technological advances, particularly the development of general-purpose graphics processing units (GPGPU) and software libraries (CUDA, OpenCL), allow to use these graphics cards power for parallel numerical computation of very high complexity and allows the use of Monte Carlo simulations of light transport in the tissues to evaluate its optical properties.

The project applicants are planning to develop methods of signal analysis and reconstruction of macroscopic optical properties (such as scattering and absorption coefficients and the anisotropy coefficient ) derived from measurements using near-infrared spectroscopy and the Monte Carlo method. The developed methods will be tested and verified on results of measurements on numerical and physical phantoms with optical properties similar to the optical properties of tissues.