Medical Glossary R

Radiation fibrosis (ray-dee-AY-shun-fye-BRO-sis): The formation of scar tissue as a result of radiation therapy to the lung.

Radiation therapy (ray-dee-AY-shun): Treatment with high-energy rays to kill cancer cells.

Radiation therapy (ray-dee-AY-shun): Treatment with high-energy rays (such as x-rays) to kill cancer cells. The radiation may come from outside the body (external radiation) or from radioactive materials placed directly in the tumor (implant radiation). Also called radiotherapy.

Radical cystectomy (RAD-i-kal sis-TEK-to-mee): Surgery to remove the bladder as well as nearby tissues and organs.

Radical prostatectomy: Surgery to remove the entire prostate. The two types of radical prostatectomy are retropubic prostatectomy and perineal prostatectomy.

Radioactive (RAY-dee-o-AK-tiv): Giving off radiatiion.

Radionuclide scanning: An exam that produces pictures (scans) of internal parts of the body. The patient is given an injection or swallows a small amount of radioactive material. A machine called a scanner then measures the radioactivity in certain organs.

Radiosensitizers: Drugs that make cells more sensitive to radiation.

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

Rectal cancer: Cancer of the rectum, a common form of cancer, is a disease in which cancer (malignant) cells are found in the tissues of the rectum. The rectum is part of the body's digestive system. The last 6 feet of intestine is called the large bowel or colon. The last 8 to 10 inches of the colon is the rectum.

Rectum: The last 8 to 10 inches of the large intestine. The rectum stores solid waste until it leaves the body through the anus.

Red blood cells: Cells that carry oxygen to all parts of the body. Also called erythrocytes.

Reed-Sternberg cell: A type of cell that appears in patients with Hodgkin's disease. The number of these cells increases as the disease advances.

Reflux: The term used when liquid backs up into the esophagus from the stomach.

Regional chemotherapy: Treatment with anticancer drugs that affects mainly the cells in the treated area.

Relapse: The return of signs and symptoms of a disease after a period of improvement.

Remission: Disappearance of the signs and symptoms of cancer. When this happens, the disease is said to be "in remission." A remission can be temporary or permanent.

Remission induction therapy: The initial chemotherapy a patient with acute leukemia receives to bring about a remission.

Renal capsule: The fibrous connective tissue that surrounds each kidney.

Renal cell cancer: Cancer that develops in the lining of the renal tubules, which filter the blood and produce urine.

Renal pelvis: The area at the center of the kidney. Urine collects here and is funneled into the ureter.

Reproductive cells: Egg and sperm cells. Each mature reproductive cell carries a single set of 23 chromosomes.

Reproductive system: The group of organs and glands involved with having a child. In women, these are the uterus (womb), the fallopian tubes, the ovaries, and the vagina (birth canal). The reproductive system in men includes the testes, the prostate, and the penis.

Respiratory system (RES-pi-ra-tor-ee): The organs that are involved in breathing. These include the nose, throat, larynx, trachea, bronchi, and lungs.

Respiratory therapy (RES-pi-ra-tor-ee): Exercises and treatments that help patients recover lung function after surgery.

Retinoblastoma: An eye cancer caused by the loss of both gene copies of the tumor- suppressor gene RB; the inherited form typically occurs in childhood, because one gene is missing from the time of birth.

Retropubic prostatectomy (re-tro-PYOO-bik): Surgical removal of the prostate through an incision in the abdomen.

Rhabdomyosarcoma: Rhabdomyosarcoma is a disease in which cancer (malignant) cells begin growing in muscle tissue somewhere in the body. Rhabdomyosarcoma is a type of a sarcoma, which means a cancer of the bone, soft tissues, or connective tissue (e.g., tendon or cartilage). Rhabdomyosarcoma begins in the soft tissues in a type of muscle called striated muscle. It can occur anywhere in the body.

Risk factor: Something that increases the chance of developing a disease.

RNA (ribonucleic acid): One of the two nucleic acids found in all cells. The other is DNA (deoxyribonucleic acid). RNA transfers genetic information from DNA to proteins produced by the cell.