Background and purpose: Failure to pay attention to the number of manpower required in hospital departments affects the efficiency and effectiveness of services. The purpose of this research is to estimate the manpower required in the radiology and CT scan units of educational and medical centers in Birjand using the WISN method.

  Research method: This study was a descriptive-cross-sectional study that was conducted in health education centers in Birjand city and the method of determining human resources based on the workload index was used. To determine the components of the workload from the method of holding expert meetings, to measure the standard time from the time measurement method, to determine the factors related to the available working time from interviews and rules and the personnel system, and to determine the annual workload through the hospital information system and checking offices activity recording was used. Excel 2016 software was used for data analysis.

  Findings: The results of workload index calculations showed that the number of radiologists and CT scan workers in educational and medical centers of Birjand city is excessive.

  Conclusion: The correct and effective organization of human resources in the hospital can guarantee the provision of safe and quality services in addition to controlling costs and increasing productivity. Health managers can increase productivity in these units by establishing a balance between the number of staff and the volume of services provided, and by emphasizing on the adjustment of emergency programs and increasing the acceptance of outpatients in medical centers.