Background: The Program of Quality Assurance (PQA) in Ionizing Radiation Therapy (IRT) addresses the most important problems of assuring the quality of IRT utilization in the treatment of patients with neoplasm. In this context, the IRT value grows considerably, hence the implementation of PQA is of great significance. The study concentrates on a detailed description of the PQA as concerns the activity involving IRT devices applied in the IRT departments (rooms) of public medical/sanitary institutions, science research institutions etc., where IRT is employed using technogenic sources and ionizing radiation generators. Material and methods: For the performing of the study, annual statistics reports about the activity of the IRT, and data of Cancer Registry of the Oncologic Institute of the Republic of Moldova were analyzed. The work also includes an in-depth description of the personnel categories involved in PQA, possible errors in radiotherapy, the responsibilities of the bioengineer in this program, importance of source calibration, the impact of the quality control in PQA, the role of topometric training, the interaction between the medical and technical personnel and the patient. Conclusions: Optimization of IRT is very important and necessary in the Republic of Moldova. PQA incontestably contributes to reducing specialist’s errors in planning correct treatment, dictates the need of team work and proper delegation of the responsibilities in co-optation of other professionals, performance of duty of bioengineering, the influence of quality control of profile installations, meaning accurate topographic planning, applying several methods of work, quality assurance program assuming the major importance.