|Ph.D Student||Zeidan Adel|
|Subject||Biomedical Imaging Using Spectral Encoding|
|Department||Department of Nanoscience and Nanotechnology||Supervisor||Professor Dvir Yelin|
|Full Thesis text|
High-resolution optical imaging for clinical applications is a rapidly developing field in biomedicine; yet, imaging speed, penetration depth and image quality remain challenging for many promising technologies. By using spectrally encoded imaging, i.e. using wavelength to encode spatial locations within a specimen, optical imaging could become faster and require less bulk, potentially enabling new instrumentation for clinical endoscopy and microscopy.
Using miniature, low numerical aperture optics and a laser-cut diffraction grating, we developed a forward-viewing spectrally encoded endoscopy probe with a wide field of view, a large number of resolvable points and low speckle noise. Effective endoscopic spectral imaging (i.e. measuring the full spectrum at each pixel), was demonstrated by continuously acquiring image data during the forward motion of the probe through cylindrical targets, which included standard resolution targets and ex-vivo blood vessels. Color imaging was also demonstrated by data post-processing and reconstructing the true color from the spectral data.
By using high numerical-aperture optics, spectral encoding allows high-resolution imaging of a single transverse line without mechanical scanning. When the imaging line is placed at the cross section of a flow channel, two-dimensional confocal images of flowing cells could be captured one axis encoded by wavelength and the other by time. Reflectance confocal microscopy of individual blood cells in vitro was used to measure the hematocrit level, the corpuscular volume, the morphology, and the flow parameters (orientation and distance from the focal plane) of individual red blood cells. The results of these experiments are currently used to develop a simple, point-of-care system for patient diagnosis.