A high-performance parallel processor utilizing 60 Inmos T800 transputers and 60 Mbytes of memory has been designed and constructed. Intended especially for applications in nuclear medicine imaging, the system has several unique features, including a global broadcast address mode via a VME bus interface and nonalgorithmic generation of random numbers in hardware. Initial performance tests demonstrate near-linear speedup for image reconstructions using the simulated annealing algorithm, and a processing speed that is over 60 times that of a VAX 8600.