How does radiation therapy work?

Radiation therapy, also known as radiotherapy, is a type of cancer treatment that uses high-energy X-rays or other forms of radiation to kill cancer cells. It works by damaging the DNA of cancer cells, causing them to either die or stop dividing.

Here's a simplified explanation of how radiation therapy works:

1. Ionizing radiation: Radiation therapy uses ionizing radiation, which means it has enough energy to remove electrons from atoms and molecules. When this happens, it creates charged particles called ions.

2. DNA damage: When ionizing radiation interacts with DNA, it can cause breaks in the DNA strands. These breaks can be repaired by the cell's natural DNA repair mechanisms. However, if the damage is too extensive or if the cell is unable to repair the damage, the cell may die.

3. Cell death: Radiation therapy primarily works by causing cell death. When radiation damage affects critical parts of the cell, such as the nucleus, the cell may not be able to survive and will eventually die. This type of cell death is called apoptosis, or programmed cell death.

4. Preventing cell division: Radiation can also prevent cancer cells from dividing. Cells reproduce by dividing into two identical daughter cells. If radiation damages the cell's DNA in a way that affects cell division, the cell may not be able to divide properly and will eventually die.

5. Targeting cancer cells: Radiation therapy aims to deliver high doses of radiation to cancer cells while minimizing damage to healthy cells. To achieve this, radiation beams are carefully shaped and directed at the tumor site using modern radiation therapy techniques like 3D conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), and volumetric modulated arc therapy (VMAT).

6. Treatment course: Radiation therapy is usually given in multiple sessions over a period of several weeks. By dividing the total dose into smaller fractions, healthy cells have time to repair and recover, reducing the risk of side effects. The specific treatment plan, including the radiation dose, number of sessions, and other details, is determined by the type of cancer, tumor location, and individual patient factors.

7. Sensitivity to radiation: Different types of cancer cells and healthy cells have varying sensitivity to radiation. Some cancer cells are more radiosensitive, meaning they are more easily damaged by radiation, while others are more radioresistant. The effectiveness of radiation therapy depends on the radiosensitivity of the cancer cells.

It's important to note that radiation therapy should be carefully planned and delivered by qualified radiation oncologists and medical physicists to ensure accuracy, effectiveness, and safety during treatment.