The small animal imaging or in vivo preclinical imaging market began to come into existence from the early 1990s when scientists studying biology and disease processes realized that clinical image could help them reduce the cost of research and time span of their animal studies. At present, medical imaging is an important tool in research applications focused toward drug discovery/ development and in the understanding of basic pathological physiology, where changes at the cellular or molecular level in animal models must be closely monitored over time. Broadly, the technology can be segmented into optical imaging, micro computed tomography (micro-CT), micro-MRI, nuclear imaging and micro-ultrasonography (micro-USG) imaging modalities. Most common small animal in vivo imaging devices used in pre-clinical applications are optical imaging and nuclear imaging modalities such as micro positron emission tomography (micro-PET) and micro single-photon emission computed tomography (micro-SPECT). Routine application of small animal imaging in bio-distribution and drug development together contributed to almost 70 percent of all application in 2014.