Lichen is the symbiotic association of a fungus (the mycobiont, which provides shelter and structure for the partnership or symbiosis), with an alga or cyanobacterium (the phoâ¦tobiont, also known as the phycobiont, which provides the food for the partnership from photosynthesis).
Some radiation therapy delivery methods include: 1  External beam radiation therapy â radiation is directed from a machine outside the body onto cancerous cells within the body.  Internal radiation therapy â radioactive material is placed (via a catheter or other carrier) directly into or near a tumor.
A common treatment for cancer, radiation oncology uses high-energy x-rays, gamma rays, electrons or radioactive materials to kill cancer cells, to stop or slow their growth and treat patients for pain or symptom relief (palliation). 1  Cancer Care Northwest provides the following radiation therapy techniques: 1  External Beam: A machine directs high-energy beams of radiation through the skin to the cancer. 2  High Dose Rate Brachytherapy: Radioactive sources are placed inside or near the tumor.