FOR OPTICAL AND/OR X-RAY IMAGING (RPOXI) DESCRIPTION The Rat Phantom for Optical and/or X-ray Imaging (RPOXI) is a complex, 3D printed rat skeleton derived from proprietary materials that are doped with X-ray opaque and/or optically active components. Luminescence is typically in the blue spectrum, but may be shifted to green or red wavelengths as needed. Stable incorporation of fluorescent species yield signal in the green, red, and cy5 filter sets of mainstream imaging devices like the IVIS or Xtreme. The RPOXI is a useful training aid during set up and installation of new optical and X-ray/CT imaging devices, preventing the need to utilize live specimens for user instruction. Further, the durable material composition provides stable signal that enables use of the RPOXI as a quality control (QC) phantom for many years of use. In some cases, the RPOXI may be used to calibrate the co-registration of X-ray/CT and optical signals during tomographic studies. Overall, RPOXI is a versatile tool for training and QC of pre-clinical imaging devices in the optical and X-ray CT space, and will be of utility in multimodal imaging labs around the globe. CONFIGURATIONS Radiopaque (X-ray/CT) and Fluorescent (Green, Red, and Cy5 Filter sets) Radiopaque (X-ray/CT) and Luminescent (blue emission) Luminescent (blue emission) and Fluorescent (Green, Red, and Cy5 Filter Sets) Proudly machined, assembled, and calibrated in th