Systems for fusion of fluorescence molecular tomography and magnetic resonance images

Methods for imaging a tumor in an animal including labeling an organ in the animal with a first detectable label detectable by both fluorescence molecular tomography (FMT) and magnetic resonance (MR) and localized substantially exclusively to the organ, whereupon the labeled organ is capable of use as a first fiducial marker in an image of the animal; administering to the animal a detectably labeled probe that localizes substantially exclusively to a region of interest in the body of the animal; after labeling the organ and administering the detectably labeled probe, imaging the animal with a FMT imager to generate an FMT image, and imaging the animal with a MR imager to generate an MR image; and aligning the FMT and MR images using the first fiducial marker as a first reference point, thereby generating an image comprising a fusion of the FMT image and the MR image.