Disease & Drug Information

Glossary of Terms

radioactive palladium

listen (RAY-dee-oh-AK-tiv puh-LAY-dee-um) A radioactive form of palladium (a metallic element that resembles platinum). When used to treat prostate cancer, radioactive seeds (small pellets that contain radioactive palladium) are placed in the prostate. Cancer cells are killed by the energy given off as the radioactive material breaks down and becomes more stable.

radioactive seed

listen (RAY-dee-oh-AK-tiv...) A small, radioactive pellet that is placed in or near a tumor. Cancer cells are killed by the energy given off as the radioactive material breaks down and becomes more stable.

radioembolization

listen (RAY-dee-oh-EM-boh-lih-ZAY-shun) A type of radiation therapy used to treat liver cancer that is advanced or has come back. Tiny beads that hold the radioisotope yttrium Y 90 are injected into the hepatic artery (the main blood vessel that carries blood to the liver). The beads collect in the tumor and the yttrium Y 90 gives off radiation. This destroys the blood vessels that the tumor needs to grow and kills the cancer cells. Radioembolization is a type of selective internal radiation therapy (SIRT). Also called intra-arterial brachytherapy.

radiofrequency ablation

listen (RAY-dee-oh-FREE-kwen-see a-BLAY-shun) A procedure that uses radio waves to heat and destroy abnormal cells. The radio waves travel through electrodes (small devices that carry electricity). Radiofrequency ablation may be used to treat cancer and other conditions.

radioimaging

listen (RAY-dee-oh-IH-muh-jing) A method that uses radioactive substances to make pictures of areas inside the body. The radioactive substance is injected into the body, and locates and binds to specific cells or tissues, including cancer cells. Images are made using a special machine that detects the radioactive substance. Also called nuclear medicine scan.

radioimmunoconjugate

listen (RAY-dee-oh-IH-myoo-noh-KON-jih-gut) A radioactive substance that carries radiation directly to cancer cells. A radioimmunoconjugate is made by attaching a radioactive molecule to an immune substance, such as a monoclonal antibody, that can bind to cancer cells. This may help kill cancer cells without harming normal cells. Radioimmunoconjugates may also be used with imaging to help find cancer cells in the body.

radioimmunodiagnostics

listen (RAY-dee-oh-IH-myoo-noh-DY-ug-NOS-tix) The use of radiolabeled monoclonal antibodies to help diagnose diseases, including cancer. The radiolabeled monoclonal antibody locates and binds to substances in the body, including cancer cells. Images are made using a special machine that detects the radioactive monoclonal antibody.

radioimmunoguided surgery

listen (RAY-dee-oh-IH-myoo-noh-GY-ded SER-juh-ree) A procedure that uses radioactive substances to locate tumors so that they can be removed by surgery.

radioimmunotherapeutics

listen (RAY-dee-oh-IH-myoo-noh-THAYR-uh-PYOO-tix) The use of radiolabeled monoclonal antibodies to treat diseases, including cancer. The radiolabeled monoclonal antibody locates and binds to substances in the body, including cancer cells. Radiation given off by the radioisotope may help kill the cancer cells.

radioimmunotherapy

listen (RAY-dee-oh-IH-myoo-noh-THAYR-uh-pee) A type of radiation therapy in which a radioactive substance is linked to a monoclonal antibody and injected into the body. The monoclonal antibody can bind to substances in the body, including cancer cells. The radioactive substance gives off radiation, which may help kill cancer cells. Radioimmunotherapy is being used to treat some types of cancer, such as lymphoma.

radioisotope

listen (RAY-dee-oh-I-suh-tope) An unstable form of a chemical element that releases radiation as it breaks down and becomes more stable. Radioisotopes may occur in nature or be made in a laboratory. In medicine, they are used in imaging tests and in treatment. Also called radionuclide.

radiolabeled

listen (RAY-dee-oh-LAY-buld) Any compound that has been joined with a radioactive substance.

radiologic exam

listen (RAY-dee-oh-LAH-jik eg-ZAM) A test that uses radiation or other imaging procedures to find signs of cancer or other abnormalities.

radiologist

listen (RAY-dee-AH-loh-jist) A doctor who specializes in creating and interpreting pictures of areas inside the body. The pictures are produced with x-rays, sound waves, or other types of energy.

radiology

listen (RAY-dee-AH-loh-jee) The use of radiation (such as x-rays) or other imaging technologies (such as ultrasound and magnetic resonance imaging) to diagnose or treat disease.

radionuclide

listen (RAY-dee-oh-NOO-klide) An unstable form of a chemical element that releases radiation as it breaks down and becomes more stable. Radionuclides may occur in nature or be made in a laboratory. In medicine, they are used in imaging tests and in treatment. Also called radioisotope.

radionuclide scanning

(RAY-dee-oh-NOO-klide SKAN-ing) A procedure that produces pictures (scans) of structures inside the body, including areas where there are cancer cells. Radionuclide scanning is used to diagnose, stage, and monitor disease. A small amount of a radioactive chemical (radionuclide) is injected into a vein or swallowed. Different radionuclides travel through the blood to different organs. A machine with a special camera moves over the person lying on a table and detects the type of radiation given off by the radionuclides. A computer forms an image of the areas where the radionuclide builds up. These areas may contain cancer cells. Also called scintigraphy.

radiopharmaceutical

listen (RAY-dee-oh-FAR-muh-SOO-tih-kul) A drug that contains a radioactive substance and is used to diagnose or treat disease, including cancer. Also called radioactive drug.

radioprotective agent

listen (RAY-dee-oh-proh-TEK-tiv AY-jent) A type of drug that helps protect healthy tissue from some of the side effects caused by radiation therapy. For example, a drug called amifostine helps reduce dry mouth in patients receiving radiation therapy for head and neck cancer.

radiosensitization

listen (RAY-dee-oh-SEN-sih-tih-ZAY-shun) The use of a drug that makes tumor cells more sensitive to radiation therapy.

radiosensitizer

listen (RAY-dee-oh-SEN-sih-TY-zer) Any substance that makes tumor cells easier to kill with radiation therapy. Some radiosensitizers are being studied in the treatment of cancer. Also called radiosensitizing agent.

radiosensitizing agent

listen (RAY-dee-oh-SEN-sih-TY-zing AY-jent) Any substance that makes tumor cells easier to kill with radiation therapy. Some radiosensitizing agents are being studied in the treatment of cancer. Also called radiosensitizer.

radiosurgery

listen (RAY-dee-oh-SER-juh-ree) A type of external radiation therapy that uses special equipment to position the patient and precisely give a single large dose of radiation to a tumor. It is used to treat brain tumors and other brain disorders that cannot be treated by regular surgery. It is also being studied in the treatment of other types of cancer. Also called radiation surgery, stereotactic radiosurgery, and stereotaxic radiosurgery.

radiotherapy

listen (RAY-dee-oh-THAYR-uh-pee) The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy or brachytherapy). Systemic radiotherapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body. Also called irradiation and radiation therapy.

radium 223 dichloride

listen (RAY-dee-um dy-KLOR-ide) A drug used to treat prostate cancer that has spread to the bone and has not gotten better with other treatment. It is also being studied in the treatment of other types of cancer. Radium 223 dichloride contains a radioactive substance called radium 223. Radium 223 collects in bone and gives off radiation that may kill cancer cells. Radium 223 dichloride is a type of radiopharmaceutical. Also called Xofigo.

radon

listen (RAY-don) A radioactive gas that is released by uranium, a substance found in soil and rock. Breathing in too much radon can damage lung cells and may lead to lung cancer.

Raftilose Synergy 1

listen (RAF-tih-lose SIH-ner-jee ...) A substance that is used to improve the health of the digestive system and bones and is being studied in the prevention of colon cancer. Raftilose Synergy 1 is made by combining two substances that occur naturally in many plants, including chicory root, wheat, bananas, onion, and garlic. Raftilose Synergy 1 helps healthy bacteria grow in the intestines and helps the body absorb calcium and magnesium. Also called oligofructose-enriched inulin.

raloxifene

listen (ra-LOK-sih-feen) The active ingredient in a drug used to reduce the risk of invasive breast cancer in postmenopausal women who are at high risk of the disease or who have osteoporosis. It is also used to prevent and treat osteoporosis in postmenopausal women. It is also being studied in the prevention of breast cancer in certain premenopausal women and in the prevention and treatment of other conditions. Raloxifene blocks the effects of the hormone estrogen in the breast and increases the amount of calcium in bone. It is a type of selective estrogen receptor modulator (SERM).

raloxifene hydrochloride

listen (ra-LOK-sih-feen HY-droh-KLOR-ide) A drug used to reduce the risk of invasive breast cancer in postmenopausal women who are at high risk of the disease or who have osteoporosis. It is also used to prevent and treat osteoporosis in postmenopausal women. It is also being studied in the prevention of breast cancer in certain premenopausal women and in the prevention and treatment of other conditions. Raloxifene hydrochloride blocks the effects of the hormone estrogen in the breast and increases the amount of calcium in bone. It is a type of selective estrogen receptor modulator (SERM). Also called Evista.

raltitrexed

listen (RAL-tih-TREK-sed) An anticancer drug that stops tumor cells from growing by blocking the ability of cells to make DNA. It belongs to the family of drugs called thymidylate synthase inhibitors. Also called ICI D1694.

ramucirumab

listen (RA-myoo-SIR-yoo-mab) A drug used with other drugs to treat colorectal cancer and non-small cell lung cancer that have spread to other parts of the body. It is used alone or with another drug to treat cancer of the stomach or gastroesophageal junction (area where the esophagus connects to the stomach) that is advanced or has spread to other parts of the body. It is also being studied in the treatment of other types of cancer. Ramucirumab binds to receptors for a protein called vascular endothelial growth factor (VEGF), which may be found on some types of cancer cells. This may prevent the growth of new blood vessels that tumors need to grow. Ramucirumab is a type of antiangiogenesis agent and a type of monoclonal antibody. Also called anti-VEGFR-2 fully human monoclonal antibody IMC-1121B, Cyramza, and IMC-1121B.

randomization

listen (RAN-duh-mih-ZAY-shun) When referring to an experiment or clinical trial, the process by which animal or human subjects are assigned by chance to separate groups that compare different treatments or other interventions. Randomization gives each participant an equal chance of being assigned to any of the groups.

randomized clinical trial

listen (RAN-duh-mized KLIH-nih-kul TRY-ul) A study in which the participants are assigned by chance to separate groups that compare different treatments; neither the researchers nor the participants can choose which group. Using chance to assign people to groups means that the groups will be similar and that the treatments they receive can be compared objectively. At the time of the trial, it is not known which treatment is best. It is the patient's choice to be in a randomized trial.

ranpirnase

listen (RAN-per-nays) A substance being studied in the treatment of cancer. It is a type of ribonuclease enzyme. Also called Onconase.

Rapamune

listen (RA-puh-MYOON) A drug used to keep the body from rejecting organ and bone marrow transplants. Rapamune blocks certain white blood cells that can reject foreign tissues and organs. It also blocks a protein that is involved in cell division. It is a type of antibiotic, a type of immunosuppressant, and a type of serine/threonine kinase inhibitor. Rapamune was previously called rapamycin. Also called sirolimus.

rapamycin

listen (RA-puh-MY-sin) A drug used to keep the body from rejecting organ and bone marrow transplants. Rapamycin blocks certain white blood cells that can reject foreign tissues and organs. It also blocks a protein that is involved in cell division. It is a type of antibiotic, a type of immunosuppressant, and a type of serine/threonine kinase inhibitor. Rapamycin is now called sirolimus.

rapid eye movement sleep

listen (RA-pid I MOOV-ment sleep) One of the five stages of sleep. During rapid eye movement sleep, the eyes move rapidly while closed and dreams occur. Rapid eye movement sleep is the lightest stage of sleep, during which a person may wake easily. During several hours of normal sleep, a person will go through several sleep cycles that include rapid eye movement sleep and the 4 stages of non-rapid eye movement (light to deep sleep). Also called REM sleep.

rapid hormone cycling

listen (RA-pid HOR-mone SY-kuh-ling) A procedure in which drugs that block the production of male hormones are alternated with male hormones and/or drugs that promote the production of male hormones. This procedure is being studied in the treatment of prostate cancer.

rapid-onset opioid

listen ( OH-pee-OYD) A substance that acts quickly to treat moderate to severe pain. Opioids are like opiates, such as morphine and codeine, but are not made from opium. Opioids bind to opioid receptors in the central nervous system. A rapid-onset opioid is a type of alkaloid.

ras gene family

listen (... jeen FA-mih-lee) A family of genes that may cause cancer when they are mutated (changed). They make proteins that are involved in cell signaling pathways, cell growth, and apoptosis (cell death). Agents that block the actions of a mutated ras gene or its protein may stop the growth of cancer. Members of the ras gene family include Kras, Hras, and Nras.

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