edema
(e-dE-ma)
An accumulation of an excessive amount of watery fluid in cells, tissues, or serous cavities.

electrocardiogram
Also called EKG or ECG.
A test that records the electrical activity of the heart that is used in diagnosing some heart abnormalities.

Electrodesiccation
The use of an electric current to destroy cancerous tissue and control bleeding.

electromagnetic radiation
Radiation consisting of electric and magnetic waves that travel at the speed of light, such as light, radio waves, gamma rays and x-rays.

electronic detector
The part of a digital imaging system that captures and converts x-rays as they pass through a patient into digital signals which are in turn sent to a computer to produce images.

electronic media
Storage media in PCs and removable/transportable digital media such as magnetic tapes or disks, CDs, pen, flash drives, optical disks, or digital memory cards; or transmission media such as the intranet, dial-up lines, and/or private networks.

electronic medical information
Patient information, including radiological images, lab test results, medications, clinical history, etc., stored on electronic media.

electronic medical record (EMR)
Computer information system that stores patients' medical information such as demographics (name, date of birth, address), clinical history, medical images, lab test results, medications, and allergies, electronically allowing healthcare providers to view the information on computers.

Electrons
Subatomic particles with mass and negative charge used in radiation therapy to treat superficially located tumors due to their physics properties.

embolic agent
A material used to block off blood flow through a vessel.

embolism
A blood clot (a thickened mass of blood) that breaks loose, travels through the bloodstream and lodges in either an organ or artery forming a complete blockage in blood flow.

embolization
The movement of a blood clot, piece of tissue, or pocket of air or gas from where it forms through the bloodstream until it lodges in place, cutting off the flow of blood with its oxygen and tissue nutrients. Catheter embolization is the deliberate introduction of foreign ("embolic") material such as gelatin sponge or metal coils to stop bleeding or cut off blood flowing to a tumor or arteriovenous malformation.

embolus, pl. emboli
A plug, composed of a detached blood clot, mass of bacteria, or other foreign body, blocking a vessel.

embryo
(em-brE-O)
In humans, the developing organism from conception until approximately the end of the second month; developmental stages from this time to birth are commonly designated as fetal.

emphysema
(em-fi-sE-ma)
A condition of the lung characterized by increase beyond the normal in the size of air spaces, with destructive changes in their walls and reduction in their number. Symptoms are undue breathlessness on exertion, due to the combined effect (in varying degrees) of reduction of alveolar (air sac) surface for gas exchange, ventilation-perfusion imbalance, and collapse of smaller airways with trapping of alveolar gas occurring predominantly in expiration; this causes the chest to be held in the position of inspiration ("barrel chest"), with prolonged expiration and increased residual volume; symptoms of chronic bronchitis often, but not necessarily, coexist.

encephalitis
An acute inflammation of the brain caused by a viral infection.

encephalography
(en-sef-u-log-ru-fE)
Radiographic representation of the brain.

encephalopathy
An alteration of normal brain function that can lead to confusion.

encryption
The process of transforming or coding information to make it unreadable to anyone except those possessing special knowledge or the key to decrypt the data.

endocrine gland
    1. A gland that produces and secretes hormones into the blood or lymph nodes, exerting powerful effects on specific tissues throughout the body.
    2. An organ consisting of specialized cells that produces and sends hormones into the bloodstream, affecting various processes throughout the body.

endometrial cavity
The space within the walls of the endometrium.

endometrium
The mucous membrane that forms the inner layer of the uterine wall; the thickness of the endometrium undergoes marked changes with the menstrual cycle.

endorectal coil
A wire coil that is inserted through a small plastic tube into the rectum as part of a magnetic resonance imaging (MRI) exam to obtain more detailed images of the prostate gland or other internal body structures.

endoscope
An illuminated optical instrument used to examine inside the body.

endoscopic retrograde cholangiopancreatography (ERCP)
An endoscope, an illuminated optical instrument, is inserted through the mouth and threaded through the esophagus to the small intestine to allow the bile duct, liver, gallbladder, and pancreas to be examined. A contrast material is then injected into the small intestine and x-rays are taken.

endoscopy
The use of an illuminated optical instrument to visualize the interior of the body and its organs.

endovaginal
Within the vagina (the genital canal in the female, extending from the uterus to the vulva).

endovaginal ultrasonography
Pelvic ultrasonography using a probe inserted into the vagina.

endovenous
Within the vein.

endovenous ablation
A minimally invasive treatment that uses heat to cauterize or burn enlarged veins in the legs, a condition called varicose veins.

enema
(en-u-ma)
A preparation that involves injecting liquid into the intestine through the rectum, or administering drugs or food to help clear the bowel.

enzyme
A protein that regulates chemical changes in other substances.

epididymis
A long, tightly coiled tube that lies behind each testicle. The epididymis collects the sperm made by the testicles.

epididymitis
An inflammation of the epididymis.

epidural analgesia
Injection of a local anesthetic into the epidural space of the spine to prevent or eliminate pelvic pain.

epidural hematoma
A collection of blood in space within the spinal canal.

esophageal reflux
A condition in which stomach contents (food or acids) move up into the esophagus, the passageway between the stomach and the mouth, and is tasted in the mouth.

esophagitis
Inflammation of the esophagus, the tube-like structure connecting the throat with the stomach.

esophagus
The "food tube" which connects the mouth to the stomach.

excisional biopsy
A type of surgical biopsy in which an entire lesion or abnormal group of cells and tissue as well as a surrounding margin of normal-appearing tissue are removed.

external beam therapy
External beam therapy is used to aim highly focused beams of radiation at the edges of the site where cancer is found in order to destroy any abnormal cells and prevent the growth or regrowth of the tumor. For more details see the External Beam Therapy page.

External Beam Radiation Therapy
Radiation therapy that uses a machine outside of the body to deliver high-energy rays directed at the cancer or tumor.