Task Specific Project 4

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Task Specific Project #4: Fluorescence Lymph Node Tomography In this Specific Task Project #4, we will integrate the parallelized adaptive finite element based tomography algorithms to the miniaturized FDPM measurement setup for maximal data flow. We break down the task of translating NIR lymph node tomography into clinic into the following four specific research aims spread over years 2 and 3 of the proposed research. CT contrast agents as well to acquire CT scanned images of the tissue phantoms that will act as gold standard images for validating tomography results. Experimental studies will be carried out to determine: (i) minimal concentration of dye required for accurate tomographic localization, (ii) minimal distance at which two node-like targets can be resolved, (iii) minimal node size which can be reconstructed, and (iv) optimal NIR excitation illumination patterns for resolving lymphatic networks. Specific Task #3 Validate tomographic measurements and algorithms for lymph node detection in Swine We expect that by the end of the first year, the mobile photogrammetric system and software will be ready and integrated with the miniaturized FDPM imaging system for clinical LN tomography. We will validate the NIR fluorescence FDPM system and algorithms in swine. In previous published work, researchers from Dr. Sevick's group have demonstrated the ability to successfully image and quantify lymph propulsion of fluorescent dyes in Yorkshire swine after ID administration [137]. In this specific aim, NIR lymph fluorescence measurements will be acquired by injecting NIR dye in three major regions: (i) along the mammary chain to visualize lymphatics draining into inguinal nodes, (ii) in the anterior and posterior hind limbs for tracking flow to inguinal and iliac and sub-iliac lymph nodes, and (iii) in the anterior and posterior forelimbs to track flow into axilla and neck regions. Twleve intradermal injections of IDOiiL each will be performed per animal; after 6 hours of imaging, animals will be euthanized. The objective of animal imaging studies under this specific aim will be to determine an optimal agent dose concentration for high fidelity reconstructed images. The optimal concentration of injected contrast agents will be determined by imaging 10 animals with the injection dose decreasing from 24 ug NIR dye per animal (that corresponds to the maximum microdose of ICG in humans) to 0.24 |jg NIR dye per animal. Reconstructed images will be analyzed with two metrics: (i) signal to noise ratio (SNR), and (ii) target to background (TBR) of the lymphatics compared to normal tissue.