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.
Palliative radiation therapy is one form of comfort care. This form of radiation isn't used to cure cancer but to treat the symptoms caused by inoperable tumors. This radiation can shrink tumors and alleviate symptoms such as bleeding, spinal cord compressions or obstructions in the throat.