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Glossary of terms

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V/Q Lung scan
A nuclear medicine exam that uses a small amount of radioactive material (called a radiotracer). The radiotracer is injected into the bloodstream and collected in the blood vessels of the lungs. A special camera takes pictures to show how blood and air are flowing throughout the lungs.

vacuum-assisted biopsy
A type of biopsy in which a vacuum-powered instrument is inserted through the skin to the site of an abnormal growth to collect and remove a sample of cells for analysis. Using vacuum pressure, the abnormal cells and tissue are removed without having to withdraw the probe after each sampling as in core needle biopsy.

The genital canal in the female, extending from the uterus to the vulva.

vagus nerve
One of two nerves that run on opposite sides of the body from the brainstem through the neck and chest to the abdomen. The vagus nerves are involved in bodily functions that are not under voluntary control, such as breathing and digestion, as well as regulation of the heart rate.

vagus nerve stimulation (VNS)
A procedure in which a device similar to a heart pacemaker is implanted under the skin and sends regular impulses of electrical energy to the brain through the vagus nerve to prevent or reduce seizures.

vagus nerve stimulator
A device similar to a heart pacemaker that is implanted under the skin and sends regular impulses of electrical energy through an electrode placed near the vagus nerve to prevent or reduce seizures. The vagus nerve sends these seizure-reducing impulses to the brain.

variceal bleeding
Bleeding from any of the veins that normally drain the stomach, esophagus, or intestines into the liver.

Dilated, fragile veins that are prone to bleeding because of the high pressure caused by portal hypertension. Varices typically arise at the junction of the esophagus and stomach, but can arise anywhere along the gastrointestinal tract.

An abnormal enlargement of a vein in the scrotum draining the testicles.

Abnormally swollen and enlarged.

varicose veins
When veins, typically in the legs, become less elastic and the one-way valves that normally prevent blood from flowing backward malfunction, blood pools in the vessels resulting in varicose or enlarged and knotty veins.

Relating to or containing blood vessels.

vascular disease
Any condition that affects the (circulatory) system of blood vessels that carries blood from the heart throughout the rest of the body. This includes diseases of the arteries, veins, and lymph vessels and blood disorders that affect circulation.

vascular stenting
Often performed with angioplasty, a procedure in which a small wire mesh tube called a stent is permanently placed in a newly opened artery to help it stay open. For details see the Angioplasty and Vascular Stenting page.

Radiography of the the secretory duct of the testicle (vas deferens), to determine patency (the state of being freely open), by injecting contrast medium into its opening either through the urethra or by incision into the vas deferens.

The narrowing of a blood vessel due to excessive contraction of the vessel wall.

One of a large system of branching vessels that collect blood which the arteries have distributed to body tissues and returns it to the heart and then the lungs.

vein stripping
A procedure in which varicose veins, abnormally swollen and enlarged blood vessels, are removed surgically, usually from the leg.

X-ray imaging of the veins following contrast material injection into the veins.

A type of x-ray in which contrast material is injected into a vein to show the details of its structure and any abnormality that may be present.

venous insufficiency
Enlarged veins with faulty valves that permit blood to pool by gravity instead of returning to the heart for re-circulation.


  1. Replacement of air or other gas in a space by fresh air or gas.
  2. Movement of gas(es) into and out of the lungs.


  1. In the brain, the hollow cavities containing cerebrospinal fluid (CSF).
  2. The main pumping chambers in the heart.

An individual bone in the column of bones that extends from the base of the skull to the pelvis which permits us to stand upright and serves to enclose and protect the spinal cord.

The bony segments of the spinal column which contain and protect the spinal cord.

vertebral compression fractures
Fractures of the vertebrae caused by the compression, or excessive pushing, of one bone against another.

An image-guided, minimally invasive, nonsurgical therapy that uses an injection of bone cement to strengthen a broken vertebra (spinal bone) that has been weakened by osteoporosis or, less commonly, cancer. See the Vertebroplasty & Kyphoplasty page for additional information.

From the bladder to the ureter – typically, the abnormal passage of urine from the bladder back into a ureter.

video capsule endoscopy
A procedure in which the patient swallows a tiny capsule holding a video camera and light. Over a period of hours, the camera sends images of the small intestine to a video recorder.

virtual private network (VPN)
A computer network in which links between computers or other hardware devices are carried on an open connection or over the Internet instead of being directly connected by physical wires; software encryption ensures that only authorized users can access the network.

An organ of the digestive, respiratory, urogenital, and endocrine systems, as well as the spleen, the heart, and great vessels; hollow and multilayered walled organs.

volumetric modulated arc therapy (VMAT)
Volumetric Arc Therapy (VMAT) is an advanced form of intensity-modulated radiotherapy (IMRT) that delivers a targeted three-dimensional dose of radiation to a tumor in one or more treatments.