Physical therapy, hemodialysis and radiation oncology departments in which patients go through lengthy and periodic treatments need to utilize their limited and expensive equipment and human resources efficiently. In such departments, it is an important task to continue to treat current patients without any interruption along with incoming patients. In this study, a patient scheduling approach for a university radiation oncology department is introduced to minimize delays in treatments due to potential prolongations in treatments of current patients and to maintain efficient use of the daily treatment capacity. A simulation analysis of the scheduling approach is also conducted to assess its efficiency under different environmental conditions and to determine appropriate scheduling policy parameter values. Also, the simulation analysis of the suggested scheduling approach enables to determine appropriate scheduling parameters under given circumstances. Therefore, the system can perform more efficiently.