Preclinical evaluation of a new mobile C-arm image amplifier with an option for three-dimensional computed tomography (CT) imaging (prototype Iso-C3D) with respect to high-contrast resolution and possible clinical applications. Cadaveric specimens (n = 30) of different joints of the lower and upper extremities and specimens of the spinal column were examined with the Iso-C3D and evaluated for image quality. In addition, using a high-contrast phantom (Catphan, Phantom Laboratory, Salem, N.Y., USA) and a fracture model of the femoral bone, measurements of high-contrast resolution were performed in comparison to spiral CT. With the exception of the shoulder, all joint regions including the entire spinal column could be examined. Adequate image quality could be achieved in smaller joints such as the wrist, elbow, ankle, and knee, whereas a remarkably decreased image quality was found when imaging the hip as well as the lumbar and thoracic spine. Images of the phantom study and high-contrast fracture model showed a high-contrast resolution comparable to helical CT (9 Lp/cm in xy-axis). In smaller joints, the image quality of the mobile C-arm CT imaging system (Iso-C3D) is comparable to that of helical CT. Image quality in examinations of the hip and lumbar and thoracic spine seems to be sufficient for intraoperative control studies of osteosynthesis. Problems still occur in shoulder examinations.