Radiation therapy is rarely used to treat CLL and not often used to treat SLL. This treatment is sometimes used to treat an enlarged (swollen) lymph node, spleen or other organ that is blocking the function of a neighbouring body part.
Radiation therapy uses high-energy X-rays, like those used to take pictures, to kill cancer cells. The X-rays cause damage to the cell’s DNA (the genetic material of the cell) which makes it impossible for the cancer cell to repair itself, so the cell dies.
Radiation does not only affect cancer cells. Healthy cells in the area will be killed off as well. Care is always taken to plan the treatment properly and ensure that other areas of the body are affected as little as possible. Healthy areas are shielded from the radiation with lead shields similar to the ones you wear at the dentist when receiving an X-ray. Lead blocks the path of any stray radiation beams and prevents them from affecting normal cells.