Abstract: In a system and method for managing repeated lock requests to synchronize an object with a particular thread, each lockable object has a lock datum and each thread can repeatedly request a lock for an object without knowing whether the thread is already synchronized with the object. Associated with each thread are a pair of locking registers and a pair of stack data structures. The registers reference the last object whose lock was acquired by the thread and contain a redundancy count indicating the number of consecutive lock requests for the object. The stack data structures contain references to other objects that are currently synchronized with the thread and an associated redundancy count for each such object. A locking procedure acquires the lock of an object only if a reference to the object is not contained in the registers or the stack data structures.

Abstract: A tomogram is obtained by tomosynthesis in a high speed CT scanning system in which fan beams of radiation are generated by sweeping an electron beam along a target, and collimated X-rays emitted by the target are received by an array of detectors after passing through a patient area between the target and array of detectors. The patient is moved through the collimated x-rays as the measurments are obtained, and the measurements are time-correlated to correspond to data measurements for a plurality of projection radiographs. The measurements for the plurality of radiographs are combined to tomosynthesize a tomogram at a selected plane in the patient.