Scheduling radiotherapy treatments for cancer patients is a major concern for hospitals and patients. The delay in radiotherapy has a negative effect on the patient and flow of patients in hospitals. This research proposes a mathematical model for multi-period radiotherapy planning and scheduling problems with capacity constraints over a particular time horizon. The goal is to schedule a list of 3D curative patients who must undergo radiotherapy. The problem is formulated with a multi-objective model with two objectives and two stages: minimize the makespan and priority score in the first stage and minimize and the sum of the finish time and the sum of different balance workloads in the second stage. Computational experiments are executed using the simulated data according to real treatments of 3D curative patients. The results show that the model satisfies all constraints with the right assignment and operation sequence. Thus, the proposed mathematical model can assist in the decision-making process for cancer patient scheduling for radiotherapy treatment. This helps reduce the time for planning and scheduling in the radiotherapy department.