Medical terms A–Z

Site selection turns less on convenience than on muscle bulk, the volume being given, and which nerves and vessels lie underneath.

Intraocular means located, occurring, or placed within the eyeball.

A rare cancer of melanocytes (cells that produce the pigment melanin) found in the eye.

Radiation treatment aimed directly at a tumor during surgery.

A procedure that uses ultrasound (high-energy sound waves that are bounced off internal tissues and organs) during surgery.

Within the pelvis, the lower part of the abdomen between the hip bones.

Within the peritoneal cavity (the area that contains the abdominal organs).

Treatment in which anticancer drugs are put directly into the abdominal cavity through a thin tube.

A method of delivering fluids and drugs directly into the abdominal cavity through a thin tube.

Treatment in which a radioactive liquid is put directly into the abdomen through a thin tube.

Intrapleural means located within the pleural cavity, the thin fluid-filled space that surrounds each lung.

Intraspinal structures, fluid, or medications are located within the spinal canal, the protected space that houses the spinal cord and its coverings.

Describes the fluid-filled space between the thin layers of tissue that cover the brain and spinal cord.

Treatment in which anticancer drugs are injected into the fluid-filled space between the thin layers of tissue that cover the brain and spinal cord.

Intratumoral means located, occurring, or administered within a tumor.

Having to do with the inside of the vagina (the birth canal).

Speed is the point and equally the catch, since nothing given by this route can be recalled once it has entered the bloodstream.

An intravenous infusion delivers fluids, medications, or nutrients directly into a vein over a controlled period rather than all at once.

The one route where absorption plays no part, which is both its great advantage and the reason it allows no second thoughts.

The x-ray picture of the urinary tract outlined by dye that the kidneys have filtered out of the blood.

The examination itself, in which timed x-rays follow dye through the kidneys and down into the bladder.

The delivery of a drug into a fluid-filled cavity within the heart or brain.

Intravesical treatments are instilled directly into the bladder through a catheter, giving higher local drug exposure while limiting effects on the rest of the body.

Placing a tube where an awake body will not tolerate one, which is why it nearly always follows sedation or unconsciousness.

Cancer that has spread from where it started in the breast into surrounding, healthy tissue.

Cancer that has spread beyond the layer of tissue in which it developed and is growing into surrounding, healthy tissues.

Cancer that has spread from the surface of the cervix to tissue deeper in the cervix or to other parts of the body.

A type of cancer that grows into the muscular wall of the uterus.

A medical procedure that invades (enters) the body, usually by cutting or puncturing the skin or by inserting instruments into the body.

A type of tumor in which surface epithelial cells grow downward into the underlying supportive tissue.

In clinical trials, refers to a drug (including a new drug, dose, combination, or route of administration) or procedure that has undergone basic laboratory testing and received approval from the U.S.

A substance that has been tested in a laboratory and has gotten approval from the U.S.

A substance that has been tested in a laboratory and has gotten approval from the U.S.

An investigator is the researcher responsible for designing, conducting, or overseeing a clinical trial or research study.

Inviable describes a pregnancy, fetus, or biological tissue that lacks the capacity to survive, develop, or function normally.

An action that is not made by choice.

The part of the nervous system that controls muscles of internal organs (such as the heart, blood vessels, lungs, stomach, and intestines) and glands (such as salivary glands and sweat glands).

A substance used to detect certain types of tumors, including pheochromocytomas and neuroblastomas.

Iodine is an essential trace element required to make thyroid hormone, obtained from foods such as iodized salt and seafood.

A form of poppy seed oil that contains iodine.

A substance that is being studied as a treatment for cancer and for primary systemic amyloidosis (a disease in which proteins are deposited in specific organs).

An ion is an atom or molecule carrying an electrical charge, essential to processes such as nerve signaling and muscle contraction.

A type of radiation made (or given off ) by x-ray procedures, radioactive substances, rays that enter the Earth's atmosphere from outer space, and other sources.

An antibiotic drug used to treat infection.

Radiation treatment aimed directly at a tumor during surgery.

A procedure that uses ultrasound (high-energy sound waves that are bounced off internal tissues and organs) during surgery.

Delivering a drug into the abdominal cavity bathes the surfaces directly, reaching concentrations that a vein could not produce at the same tissue.

A substance found in many foods that come from plants, including corn, wheat, rice, and soybeans, and in large amounts in cereals and legumes.

On the same side of the body as another structure or a given point.

An IRB is a review committee that evaluates and monitors clinical research to protect the rights and safety of study participants.

A chemotherapy drug best known for treating advanced bowel cancer, and for the severe diarrhea that can follow a dose.

The iris is the pigmented ring around the pupil that adjusts pupil size to regulate how much light enters the eye.

A condition in which the body takes up and stores more iron than it needs.

Irradiated describes tissue, an object, or a sample that has been deliberately exposed to a controlled dose of radiation.

The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors.

Side effects that are caused by toxic substances or something harmful to the body and do not go away.

Normal test results form part of the picture rather than evidence that nothing is wrong, which is the point most often misread.

A shortfall of blood supply to tissue, leaving it with too little oxygen for its needs.

A substance being studied in the treatment of oral mucositis (painful mouth sores) caused by cancer therapy and other conditions.

A pancreatic cell that produces hormones (e.g., insulin and glucagon) that are secreted into the bloodstream.

A rare cancer that forms in the islets of Langerhans cells (a type of cell found in the pancreas).

A mass of abnormal cells that forms in the endocrine (hormone-producing) tissues of the pancreas.

Beta and alpha cells sit close enough to argue with each other, which is how blood sugar is held within a narrow band.

An estrogen-like substance made by some plants, including the soy plant.

Having the same intensity as another object.

A procedure in which a catheter is placed into the artery that provides blood to the liver.

A procedure used to deliver anticancer drugs directly to an arm or leg but not to the rest of the body.

A procedure that may be used to deliver anticancer drugs directly to an arm or leg.

A surgical procedure during which the circulation of blood to the lungs is separated from the circulation of blood through the rest of the body, and a drug is delivered directly into the lung…

Isolation refers to separating a person from others, whether for infection control purposes or as a broader social or psychological state.

Same atoms in the same numbers, assembled differently, and often with a completely different effect inside the body.

Isotopes are versions of the same element with differing neutron counts, some of which are used in medical imaging and treatment.

An isthmus is a narrow band of tissue connecting two larger anatomical structures, a term applied across several different organs.

A sensation with a nerve pathway of its own, not a mild form of pain, and sometimes a sign of something outside the skin.

ITP is an autoimmune condition in which the body destroys its own platelets, lowering their blood count and increasing the risk of bruising and bleeding.

Bypassing the gut entirely means the whole amount arrives at once, which is an advantage in an emergency and a hazard in an error.

A timed series of x-rays that follows injected dye down the urinary tract to show where drainage has stalled.

A substance being studied in the treatment of cancer.

A long, hollow needle with a tapered cutting edge on one end and a handle with a place to attach a syringe on the other end.

A condition in which the skin and the whites of the eyes become yellow, urine darkens, and the color of stool becomes lighter than normal.

A substance being studied in the treatment of bladder cancer, lung cancer, and other types of cancer.

An abbreviation for a chemotherapy combination used to treat childhood ovarian and testicular germ cell cancers that have spread.

A staging system for prostate cancer that uses ABCD.

An East Indian plant that is a member of the ginger family and is used as a spice and food color.

A substance being studied in the treatment of prostate and other types of cancer.

A rare form of childhood leukemia in which cancer cells often spread into tissues such as the skin, lung, and intestines.

A tree native to West Africa.

Several tissues share the work at every joint, so pain can come from bone, cartilage, ligament or lining without the others failing.

A type of nevus (mole) found at the junction (border) between the epidermis (outer) and the dermis (inner) layers of the skin.

A rare form of childhood leukemia in which cancer cells often spread into tissues such as the skin, lung, and intestines.

Juvenile pilocytic astrocytoma, most often diagnosed in children, forms from star shaped supportive brain cells and typically grows slowly with well defined borders.

A type of cancer that begins in plasma cells (white blood cells that produce antibodies).

A combination of the drugs ritonavir and lopinavir.

A type of cancer characterized by the abnormal growth of blood vessels that develop into skin lesions or occur internally.

A Pacific island drink turned capsule, calming enough to show up in trials and tied to rare but severe liver injury.

Healing that does not know when to stop, producing a scar that keeps spreading outward long after the injury underneath has closed.

Large brown seaweed sold as a supplement, notable in medicine mainly for how much iodine it carries.

A drug that is used to treat certain types of muscle spasms and is being studied in the treatment of liver cancer.

A glycosaminoglycan (a type of polysaccharide) found in cartilage and in the cornea of the eye.

A natural substance that stimulates the growth of epithelial cells in the skin and in the lining of the mouth, stomach, and intestines.