Image-guided fiberoptic molecular imaging in a VX2 rabbit lung tumor model

Purpose: To show the feasibility of computed tomography (CT) image-guided fiberoptic confocal fluorescence molecular imaging in a rabbit lung tumor model. Materials And Methods: Eight lung tumor models were created by injection of a VX2 cell suspension. The fluorescent imaging agent IntegriSense 680 was given to the animals 3.54 hours before the procedure. CT images were obtained and transferred to the minimally invasive multimodality image-guided (MIMIG) system as a guidance map. A real-time electromagnetically tracked needle was inserted under the visual guidance of the MIMIG system. A second CT image was obtained to confirm the location of the needle tip. Next, fiberoptic fluorescence imaging was acquired along the needle track. Finally, tumor samples were obtained for histopathologic confirmation. Results: All cases were performed during breath-hold. Tumor size was 12.5 mm ± 1.6; the distance from the chest wall was 2.1 mm ± 0.5. The needle tip reached the tumor in all cases with an accuracy of 3.3 mm ± 1.6. Only one skin entry point was necessary, and no needle adjustments were required. No pneumothorax was observed. At least two-fold α _vβ ₃ integrin image contrast was detected in the tumor compared with normal lung tissue. Tumor samples were confirmed to have viable VX2 cells and contrast uptake. Conclusions: The MIMIG system enables effective in situ fluorescence molecular imaging in a needle biopsy lung procedure. In situ α _vβ ₃ integrin molecular imaging allows molecular characterization of lung tumors at multiple regions and can be used to guide biopsy procedures.