A Stochastic Model for Prioritized Outpatient Scheduling in a Radiology Center

Document Type : Original Article


1 College of Engineering, Department of Industrial Engineering, Shahed University, Tehran, Iran

2 Department of Industrial Engineering, K. N. Toosi University of Technology, Tehran, Iran


This paper discussed the scheduling problem of outpatients in a radiology center with an emphasis on priority. To more compatibility to real-world conditions, we assume that the elapsed times in different stages to be uncertain that follow from the specific distribution function. The objective is to minimize outpatients’ total spent time in a radiology center. The problem is formulated as a flexible open shop scheduling problem and a stochastic programming model. By considering the specific distribution function for uncertain variables, deterministic mixed integer linear programming (MILP) is developed such that the proposed problem can be solved by a linear programming solver in small size. Besides an effective heuristic method is proposed for the moderate size problem. To indicate the applicability of the proposed model, it has been applied to a real radiology center. The results from the proposed optimization models indicate an increase in outpatients’ satisfaction, as well as the improving of the efficiency and productivity of the radiology center.