Radiation therapy, also known as radiotherapy, is a type of cancer treatment that uses high doses of radiation to kill cancer cells and shrink tumors. Here's a technical explanation of how it works, particularly with relevance to cervical cancer.

1. Radiation Damages DNA: The fundamental principle behind radiation therapy is that it uses radiation to damage the DNA of cancer cells. DNA damage impedes the ability of cells to divide and grow, leading to cell death. Since cancer cells divide and grow faster than most normal cells, they are more susceptible to this damage.

2. Types of Radiation Therapy: There are two main types of radiation therapy, external beam radiation therapy (EBRT) and brachytherapy. For cervical cancer, both types are commonly used.

   • External Beam Radiation Therapy (EBRT): This is the most common form of radiation therapy. The radiation is delivered from a machine that directs the high-energy rays (or particles) from outside the body into the tumor. Before starting treatment, a planning session (simulation) is used to identify the precise points on the body where the radiation will be directed. The aim is to minimize exposure to healthy tissues, while ensuring that the maximum dose reaches the cancer.

   • Brachytherapy (Internal Radiation Therapy): This involves placing radioactive material inside the body, close to or inside the tumor. For cervical cancer, brachytherapy may be used to deliver a high radiation dose to the tumor while reducing the radiation exposure to surrounding healthy tissues. The radioactive source can be placed temporarily or permanently, depending on the specific treatment plan.

3. Treatment Planning: Radiation therapy is carefully planned to maximize its effect on cancer cells and minimize damage to surrounding healthy tissue. Sophisticated imaging techniques such as CT, MRI, or PET scans are used to locate the tumor and plan the route of the radiation.

4. Treatment Schedule: Radiation therapy is usually given over several weeks. The exact schedule will depend on the type and stage of the cancer, the type of radiation therapy, the total dose of radiation that's been prescribed, and the patient's general health.

5. Effect on Cancer Cells: As mentioned earlier, the radiation used in radiation therapy damages the DNA of cancer cells. This damage is often irreparable, leading to the death of these cells. While normal cells can also be damaged by radiation, they are generally better able to repair themselves.

6. Side Effects: While radiation therapy can be effective in treating cancer, it also has potential side effects, including fatigue, mild skin reactions, upset stomach, and loose bowel movements. More serious side effects might include infertility or damage to nearby organs. The medical team will closely monitor the patient for any side effects and can adjust the treatment plan or provide supportive care to help manage any side effects that do occur.

In the context of cervical cancer, radiation therapy is often used as a primary treatment. Sometimes it's used after surgery to kill any cancer cells that may remain. It can also be used to relieve symptoms in late-stage cancer. The precise approach to using radiation therapy for cervical cancer will depend on many factors, including the stage of the cancer, the patient's overall health, and the patient's personal preferences.