Medical physics is one of the most important applied branches of physics, contributing significantly to the advancement of modern medical diagnosis and treatment, particularly in oncology. This field applies physical principles such as radiation, energy, and medical imaging to develop precise and effective methods for targeting cancer cells, thereby improving treatment outcomes and survival rates. Radiation therapy is one of the primary applications of medical physics in cancer treatment. It uses high-energy radiation such as X-rays and gamma rays to destroy cancer cells by damaging their DNA, preventing them from dividing and growing. This technique is highly effective due to its ability to accurately target tumors while minimizing damage to surrounding healthy tissues. Radiation therapy techniques are classified into several main types, including external beam radiotherapy, which utilizes a linear accelerator to deliver radiation from outside the body, and brachytherapy, which involves placing radioactive sources inside or near the tumor. Additionally, proton therapy is an advanced method that uses charged particles to deliver highly precise radiation doses with reduced side effects. The medical physicist plays a crucial role in ensuring the success of treatment by accurately calculating radiation doses, optimizing treatment plans, calibrating medical equipment, and ensuring patient safety. Advanced imaging techniques such as CT and MRI scans are used to guide and plan the treatment process. In recent years, significant advancements have been made in medical physics, including the development of techniques such as three-dimensional conformal radiotherapy (3D-CRT), intensity-modulated radiotherapy (IMRT), and image-guided radiotherapy (IGRT). These innovations have improved treatment precision, reduced side effects, and enabled personalized treatment plans tailored to individual patients. The importance of medical physics lies in its ability to balance the effective destruction of cancer cells while preserving healthy tissues, thus improving patients’ quality of life. With ongoing technological progress, especially in artificial intelligence, the field is expected to witness further advancements in cancer treatment. In conclusion, medical physics is a fundamental pillar in cancer therapy, having contributed to the development of accurate and effective treatment methods. It is expected to continue playing a vital role in improving clinical outcomes and advancing cancer care in the future. Dr. Doaa Jaafar – Department of Medical Physics – College of Science Al-Mustaqbal University – The First University in Iraq