Jamal H. Ali

Near infrared spectroscopy and imaging to probe differences in water content in normal and cancer human prostate tissues.

The content of water in cancerous and normal human prostate in vitro tissues was shown to be different using near infrared (NIR) spectroscopy. The water absorption peaks at 1444 nm and 1944 nm are observed in both types of prostate tissues. The measurements show that less water is contained in cancerous tissues than in normal tissues. The OH stretching vibrational overtone mode at 1444 nm and other water overtone modes provide key spectroscopic fingerprints to detect cancer in prostate tissue. Transmission and backscattered spectral imaging were measured in cancer and normal prostate tissues. The degree of polarization for 700nm, 800nm, 1200nm, and 1450nm is larger for normal than for cancer tissues. The knowledge about water content offers a potential as a diagnostic tool to better determine and image cancer in prostate and in other tissues types such as breast and cervix using the absorption from vibrational overtones of H2O molecules in the NIR.

Detection of corrosion beneath a paint layer by use of spectral polarization optical imaging

The spectral and polarization properties of scattered light were used to image corrosion beneath the surface of a painted aluminum plate. The quality of imaging of the corrosion on the metal surface was significantly enhanced by the spectral polarization optical imaging technique. Depolarization scattered light was used to detect and image corrosion beneath the paint layer.

Imaging fluorescent objects embedded inside animal tissues using polarization difference technique

Abstract The polarization preservation property of Cardio Green dye and the fluorescence-polarization-difference-imaging (FPDI) technique are introduced to enhance the image quality of an object embedded inside tissues. The spatial FWHM resolution and contrast of the resulted fluorescence polarization difference image were found to be higher than that of the conventional non-polarized optical images by factors of 2.3 and 3.6, respectively.

Spectral polarization imaging of human rectum-membrane-prostate tissues

Human rectum-membrane-prostate tissue samples were studied using a near-infrared spectral polarization imaging technique to detect small objects and structural changes inside prostate tissues through the rectum. Four modeling samples were made with a small piece of absorber or prostate tissue dyed with a contrast agent (indocyanine green) embedded inside a large piece of prostate tissue in rectum-membrane-prostate structures. The depth of the foreign objects underneath the surface of the rectum-membrane-prostate structures was varied from a millimeter to a centimeter to obtain the critical imaging distance. Different spectral polarization imaging methods with and without contrast agents were performed and compared. The results show that small objects hidden inside the host prostate tissues in the rectum-membrane-prostate structures at depths of 2.5, 4.0, and 7.5 mm can be imaged and identified using the scattering light imaging, tissue emission wing imaging, and contrast agent fluorescence imaging methods, respectively. Our results indicate the potential of imaging and detecting structural changes and cancers inside prostate tissue though rectum-membrane-prostate tissues using this noninvasive spectral polarization imaging technique.

Visibility enhancement of fluorescent objects hidden in animal tissues using spectral fluorescence difference method

Abstract The difference between the fluorescence spectra emitted from Cardio Green dye and chicken breast tissue in the near-infrared (NIR) region was measured and used to select a pair of fingerprint wavelengths for imaging. Using spectral fluorescence difference imaging method, an 1-mm tissue object stained with Cardio Green dye located 3.1 cm underneath the surface of the host chicken tissue was clearly imaged and identified. The spatial resolution and the contrast of the fluorescence difference image were found to be significantly improved over the conventional single wavelength imaging approach.

Spectral polarization imaging of human prostate tissues

Human prostate in-vitro tissues were studied using near IR spectral polarization imaging. Different imaging methods using the light scattered or emitted from prostates tissues and contrast agents were performed on various model samples, which consisted of a small piece of absorber or prostate tissue dyed with indocayanine green embedded inside a large piece of prostate tissue at different depths. Small foreign objects with a diameter of approximately 1 mm hidden inside the host prostate tissues at depths of 3.0 mm, 4.5 mm, and 8.5 mm were imaged and identified using the scattering light, tissue emission wing and contrast agent emission light imaging methods, respectively.

Near infrared imaging of human prostate cancerous and normal tissues based on water absorption

Near-infrared imaging measurements were performed on human prostate cancerous and normal tissues. The absorption of water fingerprints in cancerous and normal tissues were studied, and used to distinguish prostate cancerous tissue from surrounding normal tissues.

Time-resolved fluorescence polarization dynamics and imaging of fluorescein dye attached to different molecular weight chains

Temporal emission profiles of fluorescein dye-labeled polymers of molecular weight range 4 K to 500 K at two polarization directions parallel and perpendicular to that of the linearly polarized exciting light were measured. The polarization decay time of dye-polymer conjugates increases with molecule weight. Images of an object containing varying molecular weight fluorescein dye-labeled polymers embedded inside turbid media were investigated. The difference image at high polymer molecular weight was found much brighter and clearer than that at low molecular weight. This observation demonstrates that high molecular weight dye-polymer conjugates can be used to enhance the imaging depth and visibility of objects hidden inside scattering media and tissues.

Randomization of coherence and polarization from the ballistic to the diffusive regimes in a highly scattering thin layer

Time-resolved measurements were performed to determine the coherence and polarization lengths in terms of the transport scattering length for highly scattering layer media. The randomization of coherence occurs at thickness (L) greater than three transport scatterers lengths (L>3 lt) and the polarization disappears after five transport scatterers lengths (L>5 lt).

Middle-IR transmission zone for corrosion and crack detection beneath paint

Transmission spectra of standard military and commercial paints were measured, and the best transmission zone was found in the middle-IR from 3.5-um to 5.7-um. Middle-IR backscattering scanning and CCD imaging approaches were developed to detect metal corrosion and small cracks underneath paint layers of up to 150-um.