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Radiation
RAY-dee-AY-shun
Energy released in the form of particle or electromagnetic waves. Common sources of radiation include radon gas, cosmic rays from outer space, medical x-rays, and energy given off by a radioisotope (unstable form of a chemical element that releases radiation as it breaks down and becomes more stable). Radiation can damage cells. It is used to diagnose and treat some types of cancer.
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Radiation Enteritis
(RAY-dee-AY-shun EN-teh-RY-tis)
Inflammation of the small intestine caused by radiation therapy to the abdomen, pelvis, or rectum. Symptoms include nausea, vomiting, abdominal pain and cramping, frequent bowel movements, watery or bloody diarrhea, fatty stools, and weight loss. Some of these symptoms may continue for a long time.
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Radiation oncologist
(RAY-dee-AY-shun on-KAH-loh-jist)
A doctor who specializes in using radiation to treat cancer.
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Radiation recall
An inflammatory reaction that can occur when certain anticancer drugs are given after radiation therapy. It usually affects the part of the body that received radiation, especially the skin. It can also affect the lungs, mouth, larynx, esophagus, other parts of the digestive tract, muscles, and the brain.
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Radiation therapy
RAY-dee-AY-shun 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).
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Radioactive
(RAY-dee-oh-AK-tiv)
Giving off radiation.
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Radiologist
(RAY-dee-AH-loh-jist)
A doctor who has special training in creating and interpreting pictures of areas inside the body. The pictures are made with x-rays, sound waves, or other types of energy.
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Radiosurgery
(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.
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Rectal
(REK-tul)
By or having to do with the rectum. The rectum is the last several inches of the large intestine closest to the anus.
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Rectally
(REK-tul-lee)
By or having to do with the rectum. The rectum is the last several inches of the large intestine closest to the anus.
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Rectum
(REK-tum)
The last several inches of the large intestine closest to the anus.
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Recurrences
(ree-KER-ents)
Cancer that has recurred (come back), usually after a period of time during which the cancer could not be detected.
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Recurrent
(ree-KER-ent)
Cancer that has recurred (come back), usually after a period of time during which the cancer could not be detected. The cancer may come back to the same place as the original (primary) tumor or to another place in the body. Also called recurrence.
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Red blood cells
A type of blood cell that is made in the bone marrow and found in the blood. Red blood cells contain a protein called hemoglobin, which carries oxygen from the lungs to all parts of the body. Checking the number of red blood cells in the blood is usually part of a complete blood cell (CBC) test. It may be used to look for conditions such as anemia, dehydration, malnutrition, and leukemia. Also called erythrocyte and RBC.
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Refractory
(reh-FRAK-tor-ee)
In medicine, describes a disease or condition that does not respond to treatment.
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Regimen
REH-jih-men
A treatment plan that specifies the dosage, the schedule, and the duration of treatment.
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Regional
(REE-juh-nul)
In oncology, describes the body area right around a tumor.
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Regional chemotherapy
(REE-juh-nul KEE-moh-THAYR-uh-pee)
Treatment with anticancer drugs directed to a specific area of the body.
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Regression
(reh-GREH-shun)
A decrease in the size of a tumor or in the extent of cancer in the body.
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Rehabilitation
(REE-huh-BIH-lih-TAY-shun)
In medicine, a process to restore mental and/or physical abilities lost to injury or disease, in order to function in a normal or near-normal way.
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Reinduction
To start over, i.e. A new treatment or protocol.
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Relapse
REE-laps
The return of a disease or the signs and symptoms of a disease after a period of improvement. Relapse also refers to returning to the use of an addictive substance or behavior, such as cigarette smoking.
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Remission
A decrease in or disappearance of signs and symptoms of cancer. In partial remission, some, but not all, signs and symptoms of cancer have disappeared. In complete remission, all signs and symptoms of cancer have disappeared, although cancer still may be in the body.
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Renal
Pertaining to your kidneys.
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Reproductive hormones
(REE-proh-DUK-tiv HOR-mone)
A type of hormone involved in fertility and sexuality. Reproductive hormones are usually made in the ovaries (in females) and testes (in males). Female reproductive hormones include estrogen and progesterone. They help develop and maintain female sex characteristics and play an important role in the menstrual cycle, fertility, and pregnancy. Male reproductive hormones, such as testosterone, help develop and maintain male sex characteristics and help make sperm in the testes. Some reproductive hormones may also be made in the laboratory and used to treat certain medical conditions.
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Research
A scientific way to examine a problem, answer a question or gain new information.
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Resection
ree-SEK-shun
Surgery to remove tissue or part or all of an organ.
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Resident
A physician in the second or third year of training after completing medical school.
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Resistance
The inherent ability of an organism to resist harmful influences.
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Respiration
The process of breathing.
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Respiratory therapist
(RES-pih-ruh-TOR-ee THAYR-uh-pist)
A health professional trained to evaluate and treat people who have breathing problems or other lung disorders.
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Respiratory tract
(RES-pih-ruh-TOR-ee trakt)
The organs that are involved in breathing. These include the nose, throat, larynx, trachea, bronchi, and lungs. Also called respiratory system.
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Retina
(REH-tih-nuh)
The light-sensitive layers of nerve tissue at the back of the eye that receive images and sends them as electric signals through the optic nerve to the brain.
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Retinoblastoma
REH-tih-noh-blas-TOH-muh
Cancer that forms in the tissues of the retina (the light-sensitive layers of nerve tissue at the back of the eye). Retinoblastoma usually occurs in children younger than 5 years. It may be hereditary or nonhereditary (sporadic).
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Reye syndrome
(ray SIN-drome)
A rare disease that damages the brain and liver and causes death if not treated.
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Rhabdomyosarcoma
RAB-doh-MY-oh-sar-KOH-muh
Cancer that forms in the soft tissues in a type of muscle called striated muscle. Rhabdomyosarcoma can occur anywhere in the body.
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Risk group
(risk groop)
In medicine, risk groups are used to describe people who are alike in important ways. For example, patients with the same type of cancer may be divided into different risk groups that depend on certain aspects of their disease. These risk groups may be based on the patients’ chance of being cured (good versus poor) or the chance that their disease will come back (high versus low). Treatment may be based on which risk group a patient falls into. Risk groups can also be used to describe people who share traits and behaviors that affect their chance of developing a disease. For example, people who do not smoke are in a lower risk group for lung cancer than people who smoke.
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Rituximab
(rih-TUK-sih-mab)
A drug used alone or with other drugs to treat certain types of B-cell non-Hodgkin lymphoma that are CD20 positive. It is used under the brand names Truxima and Rituxan to treat these cancers. Rituximab is also used under the brand name Rituxan to treat chronic lymphocytic leukemia that is CD20 positive. It is also being studied in the treatment of other conditions and types of cancer. Rituximab binds to a protein called CD20, which is found on B cells and some types of cancer cells. This may help the immune system kill cancer cells. Rituximab is a type of monoclonal antibody.
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Rothmund-Thomson syndrome
(ROT-moond-TOM-sun SIN-drome)
A rare, inherited disorder that affects many parts of the body, especially the skin, eyes, bones, hair, and teeth. The main sign or symptom is a red blistering rash on the face that begins in early infancy. Over time, the rash can spread to the arms, legs, and buttocks and cause patchy skin coloring, areas of thin skin, and small clusters of blood vessels under the skin.
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RSV
A virus that causes respiratory infections with cold-like symptoms. Also called respiratory syncytial virus.
