The presence of VM predicts poorer survival outcomes in cancer patients.

The Cypate-Bombesin Peptide Analogue Conjugate (Cybesin) was used as a prostate tumor receptor-targeted contrast agent. The absorption and fluorescence spectra of Cybesin were measured and shown to exist in the NIR tissue "optical window". The spectral polarization imaging of Cybesin-stained prostate cancerous and normal tissues shows that prostate cancerous tissue takes-up more Cybesin than that of prostate normal tissue, making Cybesin a potential marker of prostate cancer.Keywords: Prostate cancer; Receptor-targeted; Peptide analogue conjugate; Contrast agent; Spectral polarization imaging; Near-infrared; Absorption; and Fluorescence. IntroductionThe increasing incidence and mortality rate of prostate cancers in men makes early tumor detection research a challenge for oncological specialists. The region of the highest incidence is in the western world, where there are 10-11% chances for a man to develop prostate cancer, and 3-4% chances of dying from the disease (1). Conventional oncology imaging methods for prostate cancer diagnosis, still depend on bulk physical properties of cancer tissue and are not effective for earlystage primary tumors (2). It is well known that diagnosis of a small premalignant lesion is critical for the success of cancer therapy and a key to increase survival rates. Scientists have been looking for methods that emphasize gene-specific or receptor-specific, minimally invasive diagnosis for early-stage tumors (2).Near-infrared (NIR) optical imaging is a powerful tool in cancer research that relies on activating endogenous chromophores or applying contrast agents that can target cancer cells. The use of intrinsic chromophores to differentiate the optical properties of diseased and healthy human tissues has been reported in some studies using fluorescence and absorption (3, 4). The most attractive advantage of optical imaging is the high sensitivity, which can be superior to other in vivo imaging techniques (2). Over the past decade, cyanine dyes have been investigated by several groups (5, 6) as contrast agents for optical detection of tumors. In order to observe fluorescence from a substantial distance within the body, the emission wavelength must be in the NIR wavelength window in which light passing through tissue is less likely to be absorbed or scattered (7). Researchers are interested in cyanine dyes because their emission range of 700 nm to 900 nm is in the tissue "optical window" (8 absorption bands at 950nm and 1195nm due to water which is the main chromophore component in human tissue (4, 9).The investigations of receptor expression in normal and cancer tissue suggest that small peptide-dye conjugates can be used to target over-expressed receptors on tumors contrary to the traditional approach of dyes conjugated to large proteins and antibodies (5, 10, 11). As a small ICG-derivative dyepeptide, Cypate-Bombesin Peptide Analogue Conjugate (Cybesin) was synthesized and used as a contrast agent to detect pancreas tumors in an animal model a few years ago (5). The prior experimenta...

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 H 2 O molecules in the NIR.

Light scattering and transmission of Gaussian (G) and Laguerre-Gaussian (LG) vortex beams with different orbital angular momentum (L) in various turbid media were investigated. Transmittance was measured with varied ratios of sample thickness (z) to scattering mean free path (l_s) of turbid media, z/l_s. In the ballistic region, the LG and G beams were found to have no significant difference on transmittance, while in the diffusive region, the LG beams showed a higher received signal than the G beams, and the LG beams with higher L values showed a higher received signal than those with lower L values. The transition points from ballistic to diffusive regions for different scattering media were determined. This newly observed transmittance difference of LG and G beams may be used for deep target detection in turbid media through LG beam imaging.