These types of radiation are considered local therapy because the radiation is from a solid source, meaning that it only treats cancer in the area near the radiation source.
Another type of internal radiation therapy treats with radiation from a liquid source. It is administered in pill form, intravenously, or by injection. The radiation travels through the bloodstream, seeking out cancerous cells in the body’s tissues. This is used to treat different types of cancer and is often used to control pain from cancer that has spread to the bones.