Abstract Radiation protection is fundamental to the safe medical use of ionizing radiation. It aims to achieve diagnostic and therapeutic benefits while avoiding unnecessary exposure and reducing the potential for harm. Medical physics contributes through dosimetry, equipment quality control, optimization of imaging and treatment protocols, and support for occupational protection. This article discusses radiation protection principles and their practical applications, emphasizing training and multidisciplinary cooperation in promoting safety. Keywords: Radiation protection, medical physics, patient safety, occupational exposure, dosimetry, quality assurance. Introduction Ionizing radiation has advanced diagnosis and treatment through applications including X-ray imaging, computed tomography, nuclear medicine, and radiotherapy. These benefits require controlled exposure, appropriate procedures, and accurate delivery. Radiation protection provides a framework for balancing medical benefits against potential risks, while medical physics helps translate this framework into measurable practices within healthcare facilities. Fundamental Principles of Radiation Protection Radiation protection is based on justification, optimization, and the application of dose limits where applicable. Justification requires the expected benefit of a procedure to outweigh its potential radiation harm. Optimization seeks exposure appropriate to the medical purpose while avoiding unnecessary dose. Occupational and public dose limits do not apply to patients undergoing diagnosis or treatment; patient protection relies primarily on justification and optimization. In medical imaging, optimization means obtaining sufficient image quality to answer the clinical question at an appropriate dose. In radiotherapy, it involves delivering the prescribed dose to the treatment target while limiting exposure to healthy tissues as far as reasonably achievable. The Role of Medical Physics in Patient Protection Medical physicists support patient protection by assessing equipment performance, measuring doses, and verifying system accuracy. Depending on their specialty, their responsibilities include equipment acceptance testing, calibration, quality control, and protocol optimization. In diagnostic imaging, diagnostic reference levels help evaluate practice and identify typical dose levels that warrant investigation. They are optimization tools rather than individual patient dose limits, and a lower dose alone does not establish examination quality. In radiotherapy, physical measurements and verification support accurate dose calculation and delivery, helping detect deviations before they affect treatment. Protection Against Occupational Exposure Protection against external radiation combines time, distance, and shielding: minimizing unnecessary time in radiation fields, increasing distance where practical, and using suitable barriers. These principles should inform facility design and work organization. During image-guided interventional procedures, the patient is a major source of scattered radiation reaching staff. Appropriate positioning, ceiling-suspended shields, under-table shielding, and suitable protective equipment are therefore important. Individual dose monitoring supports occupational exposure assessment and the review of working practices. Procedures involving unsealed radioactive materials also require measures to control contamination and prevent radioactive substances from entering the body. Quality Assurance and Error Prevention Quality assurance connects technical performance with procedural safety. Safe practice includes verifying patient identity, the intended procedure, the anatomical region, and equipment settings, alongside routine maintenance and documented testing. Reviewing incidents and near misses helps identify weaknesses and improve systems before errors recur. Safety requires clearly assigned responsibilities and cooperation among physicians, medical physicists, radiographers, and radiation protection officers, within their respective roles. Training, Communication, and Safety Culture Equipment and shielding alone cannot ensure protection. Continuing training, adherence to procedures, and encouragement to report problems are also necessary. Patient communication should explain expected benefits and relevant risks in understandable language appropriate to the procedure. IAEA guidance emphasizes providing patients with suitable information about benefits and radiation risks. Conclusion Medical physics supports patient and staff safety through accurate measurement, quality control, procedural optimization, and performance verification. Effective radiation protection integrates these activities with clinical justification, training, communication, and a strong safety culture, preserving the medical benefits of radiation while limiting unnecessary exposure. Almustaqbal University – The First University in Iraq