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Spatial diffusion reflection (DR) measurements of gold nanorods (GNR) were recently suggested as a simple and highly sensitive non-invasive and non-ionizing method for real-time cancer detection. In this paper we demonstrate that wavelength dependent DR measurements enable the spectral red-shift observation of highly concentrated GNR. By conjugating targeting moieties to the GNR, large density of GNR can specifically home onto cancer cells. The inter-particle plasmon resonance pattern of the highly concentrated GNR leads to an extension and a red-shift (Δλ) in the absorption spectrum of the concentrated GNR. Dark-field microscopy was used in order to measure the expected Δλ in different GNR concentrations in vitro. Double-wavelength DR measurements of tissue-like phantoms and tumor bearing mice containing different GNR concentrations are presented. We show that the DR profile of the highly concentrated GNR directly correlate with the spectral extension and red-shift. This presented work suggests that wavelength dependent DR method can serve as a promising tool for real-time superficial tumor detection.

Utilizing the surface plasmon resonance effect in gold nanoparticles enables their use as contrast agents in a variety of applications for compound cellular imaging. However, most techniques suffer from poor signal to noise ratio (SNR) statistics due to high shot noise that is associated with low photon count in addition to high background noise. We demonstrate an effective way to improve the SNR, in particular when the inspected signal is indistinguishable in the given noisy environment. We excite the temporal flickering of the scattered light from gold nanoparticle that labels a biological sample. By preforming temporal spectral analysis of the received spatial image and by inspecting the proper spectral component corresponding to the modulation frequency, we separate the signal from the wide spread spectral noise (lock-in amplification).

Absrrucr-The pinned sine transform (PST) coder described is a practical approximation to the pinned KLT coder. The image is partitioned into two fields: a bounduryfield, which depends only on the coded block boundaries, and a pinned field, which vanishes at the boundaries and is subsequently sine transformed and compressed. The reconstructed image is continuous across the block boundaries and "blocking effects" are hardly visible. Simulation results are given for fixed and adaptive compression schemes with fair image quality at low hit rates down to 0.3 hits/pel.