In this work, we present a novel,
simple, and highly accurate three-dimensional
(3D) diffusion reflection (DR) imaging system and method for the detection
of accumulation sites of gold nanorods (GNRs) within the tissue. GNRs
are intensively used for diagnosis purposes of varied diseases, mainly
because of their ability to well absorb visible light, which introduces
them as terrific contrast agents in various imaging and theranostics
methods. Lately, these GNRs unique absorption properties have served
in DR intensity-based measurements, suggesting a novel diagnostic
tool, DR-GNRs. In this paper, we show a new measurement system and
method for DR, based on its radial collection from the tissue. These
radial measurements enabled a unique 3D presentation of the DR-GNR,
introducing the dimensions ρ for the radius, θ for the
angle, and Γ for the reflected intensity. On the basis of the
diffusion model, which enables to correlate between the sample’s
optical properties and its reflectance, a unique, radial map is presented.
This map introduces the slopes of the DR curves in each measured angle,
which are linearly correlated with the tissue’s optical properties
and with the GNRs concentrations within the tissue, thus enables the
exact radial localization of the GNRs in the sample. We show the detection
of macrophage accumulation in tissue-like phantoms, as well as the
localization of unstable plaques in hyperlipidemic mice, in vivo.
This highly accurate, powerful technology paves the way toward a real-time
detection method that can be successfully integrated in the rapid
increasing field of personalized medicine.