balloon angioplasty
An image-guided procedure in which a balloon-tipped catheter, a long thin, hollow plastic tube, is guided into an artery and advanced to a blockage or narrowing in a blood vessel. The balloon is then inflated to open the vessel, deflated and removed.

balloon assisted technique
A technique that uses balloons to open narrowed blood vessels.

barium (Ba)
(ba-rE-um, bA-rE-um)
A metallic, alkaline, divalent earth element; atomic no. 56, atomic wt. 137.327. Salts are often used in diagnosis.

barium sulfate
A white insoluble radiopaque powder that is used as a contrast material to make certain body parts more visible in x-ray images. Radiopaque substances limit the penetration of x-rays and other forms of radiation.

baseline
Initial.

Beam Films
Images created by the radiation beams themselves. They are used to verify the position of the beams to confirm that treatment is accurately delivered to the right place. Also known as port films.

becquerel (Bq)
(bek-rel)
The SI unit of measurement of radioactivity, equal to 1 disintegration per second;;
1 Bq = 0.027 × 10-9 Ci.

benign
(bE-nIn)
Not cancerous. May also be defined as non-malignant. Benign is also used to describe medical conditions that have a mild course.

benign prostatic hyperplasia (BPH)
An enlarged prostate gland common in older men.

beta blocker
A type of medicine used to lower blood pressure, treat chest pain and heart failure, and to prevent a heart attack.

bile
A greenish-yellow fluid secreted by the liver, stored in the gallbladder and released through tubular passageways called bile ducts into the bowel to help digest fat and carry away waste.

bile ducts
Tubular passageways in the liver that carry bile, a greenish-yellow fluid secreted by the liver, to aid in the digestion of fat and transport waste out of the liver.

biliary system
See biliary tract.

biliary tract
Also called the biliary system.
Includes the gallbladder and tubular structures called ducts that course through the liver. Bile, a greenish-yellow fluid secreted by the liver, is stored in the gallbladder and released into the bowel through bile ducts to help the small intestine digest fat and carry away waste.

Biologic Therapy
Also called immunotherapy, biologic therapy works with your immune system to fight cancer. Biologic therapy is like chemotherapy. The difference is that chemotherapy attacks the cancer directly and biologic therapy helps your immune system fight the disease better.

biologically active coils
A type of coil, made of soft platinum wire smaller than a strand of hair and available in different diameters and lengths, used in a procedure called a detachable coil embolization to treat an aneurysm (a bulge) or a blood vessel malformation called a fistula (a false passageway) that occurs in the brain and other parts of the body. Using image guidance, the coils are placed at the site of a bulge or passageway, where it helps block the flow of blood and prevents a rupture of the vessel.

biometrics
Biometrics requires a user to provide a unique identifier, such as a fingerprint or voice sample, which is compared to a stored record before the user can gain access to the computer.

biopsy
(bI-op-sE)
1.Process of removing tissue from living patients for diagnostic examination.
2.A specimen obtained by biopsy.

bladder
A balloon-like organ where urine is stored before being passed from the body.

bleeding disorder
A condition in which the body's blood clotting mechanism, which turns blood from a free-flowing liquid to a thickened state, is defective.

Blocks
Pieces of metal alloy that can be used to shape the radiation beam from a linear accelerator.

blood clot
A thickened mass of blood.

blood clotting
See blood coagulation.

blood coagulation
Also called blood clotting. A process in which blood changes from a free-flowing liquid to a semi-solid gel.

blood oxygenation
The level of oxygen in the blood.

blood thinning agents
Also known as blood thinners. Medicine used to prevent blood clots from forming or getting larger.

Bolus
Additional material placed on the patient's skin to intentionally pull the radiation dose more superficially.

boost
An additional dose of radiation delivered after an initial course of radiation. A boost is usually a smaller treatment in volume and is used to enhance tumor control.

bore
The center of the cylindrical shaped magnet (often referred to as a doughnut) within an magnetic resonance imaging (MRI) scanner.

bowel
The part of the digestive system distal to the stomach, consisting of the small and large intestines, that digest and eliminate food.

bowel cancer
See colorectal cancer.

brachytherapy
(bray-key-therapy)
Also called internal radiation therapy. A type of radiation therapy used to treat cancer, involving the placement of a radioactive material, either temporarily or permanently, directly inside the body.

brain herniation
An often fatal condition that results when brain tissue, fluid or blood vessels are pushed outside the skull.

brain mapping
Mapping the brain's surface using small electrodes to stimulate a nerve so its electrical response can be measured. By determining the role of specific nerves in a patient, this technique helps surgeons avoid damage to sensitive areas while operating on the brain.

breast coil
A wire coil placed around the breast that sends and receives radio waves within the magnetic field of an MRI unit to create images.

bronchi
The large air passages that lead from the trachea (windpipe) to the lungs.

bronchiectasis
An abnormal condition of the bronchi (the "breathing tubes"), often caused by infection. Serious complications may occur, and some patients require surgical removal of the affected part of the lungs.

bronchitis
(brong-kI-tis)
Inflammation of the mucous membrane of the two subdivisions of the trachea (air tube) that conveys air to and from the lungs.

bronchoscope
An instrument for examination of the trachea and bronchi.

bronchoscopy
Visual inspection of the inside of the trachea and the bronchial passages of the lungs, using a rigid or flexible tube.

bruit
An abnormal sound heard when listening with a stethoscope over an organ or blood vessel such as the carotid artery in the neck.

Budd-Chiari syndrome
A blockage of one or more hepatic veins, which carry blood from the liver back toward the heart.

bulla
A thin-walled air "cyst" within the lung, found in patients with emphysema.

bursa, pl. bursae
(bur-suh)
A closed sac or envelope lined with a membrane and containing lubricating fluid, usually found or formed in areas subject to friction; e.g., over an exposed or prominent part or where a tendon passes over a bone.