1. A method of imaging a subject animal, comprising: treating the animal with an x-ray contrast agent and an optical imaging agent; supporting the animal in an immobilized state on a support member; providing a phosphor plate adapted to be disposed proximate the support member when capturing a first image; with the phosphor plate disposed proximate the support member, imaging the immobilized animal in a first imaging mode to capture the first image, the first imaging mode being an x-ray mode; removing the phosphor plate from proximate the support member, after capturing the first image and without moving the immobilized animal and the support member; and with the phosphor plate removed from proximate the support member, imaging the immobilized animal in a second imaging mode to capture a second image, the second imaging mode being an optical dark-field mode.