The IVIS® SpectrumCT pre-clinical in vivo imaging system expands upon the versatility and advanced optical feature sets of the IVIS and Maestro™ platforms integrated with low dose microCT to support longitudinal imaging. The IVIS SpectrumCT enables simultaneous molecular and anatomical longitudinal studies, providing researchers with essential insights into complex biological systems in small animal models. The constant horizontal gantry motion and the flat panel detector provide low-dose imaging and automated optical and microCT integration. The stable revolving animal platform table rotates 360° to acquire full 3D data. Multiple animals can be scanned simultaneously while maintaining an average dose per scan at about 13 mGy, with a scanning and reconstruction time of less than a minute. Optical and microCT modalities can also operate independently. Multispectral fluorescence imaging (400-900nm wavelength) can be performed with the system for 2D or 3D imaging. Deep tissue detection and quantification can be achieved through trans-illumination available on this system. The system is fully equipped with its own isoflurane anaesthetic system and is capable of imaging up to five mice simultaneously.