Radiotherapy is a common form of cancer treatment that uses high-energy radiation to target and destroy cancer cells. It can be delivered externally using a machine that directs radiation beams at the tumor, or internally through the placement of radioactive materials directly inside the body near the tumor. Radiotherapy works by damaging the DNA of cancer cells, preventing them from growing and dividing. It is often used in combination with other treatments such as surgery or chemotherapy to provide a comprehensive approach to cancer care. Radiotherapy is a highly specialized field that requires expertise in medical physics, radiation oncology, and radiobiology. Treatment planning is carefully tailored to each individual patient to maximize the effectiveness of the radiation while minimizing damage to surrounding healthy tissues. Overall, radiotherapy plays a critical role in the treatment of many types of cancer and can be an essential part of a patient's treatment plan.