A surgical device is disclosed which may advantageously perform the functions of both a retractor and a distractor. A set of detector output data that represent beams over a specific angular range and a scan of a specific subregion of the object, are divided into m\u22672 complete partial detector output data records that respectively cover the same complete angular range, but are reduced with their sampling density by 1m and have mutually independent data records. A collar is joined to the inner band and has a slot formed therein. The monitored data could also be readily associated with records of the patient and other physiological could data of the patient that may have been prestored in the controller to which the finger grip device is connected, or in a memory at a remote location.