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Surface Plasmon Resonance Optical Tomography with Gold Nanoparticles

K Xu

K Xu1,2, J Shi1 , N Dogan1,2 , W Zhao2 , Y Yang1,2* , (1) Department of Radiation Oncology, University of Miami School of Medicine, Miami, FL, (2) Department of Biomedical Engineering, University of Miami School of Engineering, Miami, FL


TH-AB-708-10 (Thursday, August 3, 2017) 7:30 AM - 9:30 AM Room: 708

Purpose: To develop a new optical imaging technique: surface plasmon resonance optical tomography (SPROT), which utilizes gold nanoparticles (GNP) to enhance diffuse optical tomography (DOT).

Methods: The GNP used were gold nanorods (10nm by 45nm) which has strong light absorption peaked at 850nm due to the surface plasmon resonance phenomenon when incident light interacts with the electric field on the particle surface. 0.11ml GNP suspension at 46.5nM concentration was sealed in a 6mm glass ball, which was implanted into the abdomen of a 5-week old nude mouse cadaver as an imaging target. An 856nm (60mW) laser beam with 1mm focal spot on the animal surface was used as irradiation light source. Projection images of light transmission were acquired from 25 source locations (5 rows, 5 columns, 3mm spacing) at anterior-posterior and posterior-anterior directions, respectively, for tomographic reconstruction. Both DOT and Cone Beam CT (CBCT) were acquired, before and after glass ball implantation. The pre- and post-implantation images were registered based on the bony landmarks in the CBCT. The difference between the post- and pre-implantation DOTs indicates the distribution of GNP. The radiopaque glass ball on the CBCT was used as the ground-truth location of the GNP volume.

Results: Both pre- and post-implantation DOTs reconstructed the high-light-absorption area in the mouse abdomen. The post-implantation DOT itself could not separate the GNP volume from the high-absorption gastrointestinal volume. The subtraction image, however, recovered the GNP volume with <2mm error.

Conclusion: Gastrointestinal tract, because of its large volume and strong light absorption by its food content, caused image artifact in DOT and imposed difficulty in GNP detection. Despite this, GNP at 46.5nM concentration (0.2% weight) was successfully recovered from the subtraction image. The result confirmed the feasibility of SPROT imaging of gold nanoparticles.

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