Recent technological advances have permitted the non-invasive imaging of tumor xenografts as well as molecular events associated with tumor progression. One of the limitations of the current platforms is an inability to obtain tomographic images of bioluminescent tumors. Despite the new Xenogen IVISÂ® Imaging System 200 Series recently available, some current owners of the 50 and 100 Series are unaware of the ability of these technologies to generate useful topographic or tomographic images. We injected immunodeficient mice subcutaneously in 0, 90, 180, and 270 degree positions with 5 x 10E6 HCT116 colon cancer cells expressing the luciferase reporter genes. This was performed in order to allow imaging of lesions from multiple viewpoints. After intraperitoneal injection of ketamine and D-luciferin, a mouse was taped onto a clear glass or plexiglass platform resting between two heavy blocks on top of the imaging chamber stage. Aside from adjusting the angle of the platform every 30 degrees from 0 to 360 degrees, the photographic and luminescent images were acquired according to Xenogen’s instructions. Significant photon counts were detected through both the glass and plexiglass platform materials. Representative photon counts are as follows: left tumor (average in all images was 2011 +/−2872, maximum value of 6837), ventral tumor (average of 2835 +/− 3774, maximum of 8200), right tumor (average of 2968 +/− 4970, maximum of 16698), and dorsal tumor (average of 8072 +/− 10175, maximum of 16959). Based upon this proof-of-principle data, we are building a low cost, after market hardware solution that avoids the unnecessary purchase of the expensive IVIS 200 model for current Xenogen owners. This robotic arm does not make any modifications to the Xenogen product, e.g. drilling holes, and will permit multi-view optical information recorded from various source positions to generate 3D topographical images. Coregistration with other anatomical tomographic imaging modalities is providing insights into the origins and depth of bioluminescent signals for tumor growth and therapeutic response studies.
[Proc Amer Assoc Cancer Res, Volume 46, 2005]