Dictionary

radiation therapy, external Radiation therapy in which the source of radiation is a machine outside the body.

radiation therapy, internal Radiation therapy in which a small container of radioactive material is implanted in the body, in or near the cancerous tumor.

radiation therapy, interstitial A form of radiotherapy in which tiny radioactive “seeds” are implanted directly in the affected tissue with a needle-like instrument. Interstitial radiation therapy has been used in the treatment of prostate and other cancers.

radiation therapy, stereotactic The use of a number of precisely aimed beams of ionizing radiation, each coming from a different direction and meeting at a specific point, to deliver radiation treatment to that spot.

radical dissection Surgical removal of not only affected tissue, but also nearby tissue that may be covertly affected.

radical neck dissection Often called a “radical neck,” a surgical procedure that involves the removal of a tumor from the neck with an additional margin of seemingly normal tissue of at least 2 cm together with the removal of the lymph nodes from the neck.

radiculitis See radiculopathy.

radiculopathy Any disease of the spinal nerve roots and spinal nerves. Radiculopathy is characterized by pain that seems to radiate from the spine, extending outward to cause symptoms away from the source of the spinal nerve root irritation. Causes of radiculopathy include deformities of the discs between the vertebrae. Patients with diabetes can be affected…

radioactive Emitting energy waves due to decaying atomic nuclei. Radioactive substances are used in medicine as tracers for diagnosis and in treatment to kill cancerous cells.

radioactive iodine A version (isotope) of the chemical element iodine that is radioactive. Abbreviated RAI. RAI is used in diagnostic tests as well as in radiotherapy of the thyroid. It may be used in the treatment of hyperthyroidism and cancers of the thyroid. It directly radiates thyroid tissues, thereby destroying them. RAI should not be…

radioactive tracer A radioactive molecule that can be sent through the body’s circulatory or urinary system, with its progress followed by a radiation-sensitive machine.

radioallergosorbent test See RAST.