The major goals of this project are: (1) to assess the effect of an image management system on patient flow and work process of a Radiology Department and an Emergency Department and (2) to develop a computer- based mathematical model for simulating the patient flow and work processes. The main hypotheses are: (1) the use of a PACS will speed up patient flow and improve a Radiology Department's work process of providing diagnostic imaging services and delivering image information to the referral physicians" (2) the rapid flow for patients and image information in Radiology may speed up patient flow and work process in an Emergency Department; and (3) by making rapid, iterative technological and non-technological (e.g., organizational and management) interventions, one can integrate the PACS into the day-to- day life of the referral physicians and further improve patient flow and work process in the ED. These hypotheses are based on the assumption that the process of patient care in an ED is a complex system which takes many kinds of input and involves a chain of interdependent activities. The implementation of a PACS may affect patient flow and work process in Radiology which in turn may speed up patient flow and work process in an ED . Four indicators will be used to assess the effectiveness of a Radiology Department's work process: (1) time interval between when a radiological examination is ordered and the image information becomes available to the referral physicians; (2) the frequency with which requested comparison examinations are available; (3) time interval between when an exam is completed and comparison examinations become available; and (4) physicians' satisfaction with the timeliness and quality of radiologic services, Another set of four indicators will be used to measure the effectiveness of an Emergency Department's patient care process: (1) time interval between a patient's arrival and physician assessment; (2) total patient time in the ED; (3) time interval between the availability of requested image information and physicians' access to the information; and (4) patient satisfaction with the timeliness and quality of services provided in the ED. Standard multivariate statistical methods (e.g., multivariate regression) will be used to determine the effect of the PACS on these processes after controlling for patient case mix and other confounding factors. The simulation model will use quantitative models of queuing and scheduling that have been used widely in industrial engineering and operations research. The simulation model will be used for two purposes: (1) to assess the role of a PACS in the process of patient care under various hypothetical situations and (2) to help the project team identify process bottlenecks and opportunities for making organizational and managerial changes in order to integrate the technology into the day-to-day life of the referral physicians.