<p>(a) Photograph of the paper phantom laid flat. Each letter and the spot beneath was pipetted on to paper using different SERS nanoparticle flavors (‘S’ = S493,‘P’ = S440, ‘E’ = S482, ‘C’ = S420, ‘T’ = S481, ‘R’ = S421). The ‘A’ and spot below were composed of an equal mixture of all six flavors at one-fifth the concentration; thus appearing dimmer than the other letters. The spots under each letter were below 1 mm in diameter, which is less than the size detectable with white-light endoscopy. (b) Photograph of the phantom with a radius set to 25 mm to mimic the average human colon radius. (c) Image of signal intensities of S493, S440, S482, S420, S481, and S421 shown as 2-D images. (d) Cylindrical three-dimensional reconstruction of the data acquired with the device showing a 5-cm segment of the phantom lumen. (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0123185#pone.0123185.s002" target="_blank">S2 Video</a>). There are a total of 5,000 pixels (50 rev x 100 pix/rev) acquired, which was obtained in a period of 50 seconds (1 rev/s). Each of the SERS flavors was assigned a specific color.</p
