The objective of this proposal is to purchase a three-dimensional micro computed tomography scanner. The system has the capability of digitizing the three-dimensional architecture of biologic specimens at a resolution between 5 and 100 microns. This system will essentially replace a system that has been part of a Core facility operation at the University of Michigan for the past 17 years and has supported more than 130 faculty. The principal rationale for the purchase of this new system is based on needs of a large group of well funded investigators and the catastrophic failure that has occurred in the system that was in operation. The data which can be acquired by the 3D Micro CT system enables investigators to study mechanisms associated with skeletal diseases ranging from age associated osteoporosis to genetic diseases such as osteogenesis imperfecta and evaluating the potential for therapies including the development of tissue engineered constructs and other regenerative medicine strategies. An additional significant use of the system is in support of evaluating fundamental mechanisms regulating the function of the skeleton as modeled in small animals. ? ? ?