Tracking the former location of a radioactive source represents an attractive attribute in today's society, where the threat of a radiological dispersal device (RDD) is considered high. Development of a novel, retrospective detection technique based on optically stimulated luminescence is underway. This will allow confirmation of the former location of a radioactive source. Materials near the source's former location may be probed for information on accumulated dose by taking advantage of radiation-induced charge trapping that occurs in many common materials. The prototype detector design and analysis techniques are described.