Diffuse Optical Imaging: Safe and Functional Medical Imaging Technique - Diffuse Optical Imaging: Safe and Functional Medical Imaging Technique - Open Access Pub

Optical imaging method provides safe and encouraging tool in many medical applications. In this editorial, principle operation, instrumentation, medical applications and advantages of diffuse optical imaging technique are presented and discussed. DOI10.14302/issn.2641-4538.jphi-18-2190 Diffuse Optical Imaging technique or shortly “DOI” provides a spatial distribution of tissue optical properties and related physiological parameters, the tissue is probed with light and the transmitted light distribution on the tissue surface is measured. The measured data then become an input to a model-based iterative image reconstruction scheme 1. It is called diffuse because the light propagates diffusely through any turbid medium such as biological tissues due to the effect of multiple and denes scattering property 2.The technique utilizes light in the red and near infrared spectral range to measure tissue physiology non-invasively due to its high penetration depth in biological tissues at that region 3. To apply the diffusion model, light is detected at predetermined distances from the sources (source-detector pairs). Light can be detected in either reflection or transmission geometry through a section of thick tissue 4, 5. The measured tissue optical parameters which are absorption coefficient, scattering coefficient and anisotropy are highly related to important physiological changes in tissues like hemoglobin and melanin concentrations and tissue water content as well. According to the type of light source used in imaging, diffuse optical imaging device can be divided into three categories; steady state or continues wave (CW), time-domain, and frequency domain FD imaging. Frequency domain technique can be classified to frequency domain photon migration FDPM or spatial frequency domain imaging SFDI 6. Each technique has its benefit, the CW technique is considered inexpensive, fast and commercially accessible, it can be useful for measuring relative changes in tissue chromophores, however, this method can’t directly separate absorption from scattering measurements without utilizing a suitable mathematical model. In time- domain (or time-resolved) techniques pulses of light are delivered to the sample and time gated and/or single photon counting detectors are used to measure the attenuation of the source pulse after propagation through the tissue, an analysis of the detected signal (temporal point spread function, t-PSF) can distinguish between tissue absorption and scattering 7. In time domain imaging, the source is a sharp temporally focused beam and after