· IMRT Intensity Modulated Radiotherapy. Specialized equipment that shapes radiation beams to the size and shape of a tumor. The tumor is treated with many very small beams, each of which can have a different intensity. By cross firing, a relatively uniform dose of radiation is delivered to the tumor while sparing surrounding tissue from high doses. IMRT can be used to treat large malignant tumors and multiple tumors.
· in situ cancer Cancer that is confined to a small area and has not spread.
· intra-operative [OP-er-ah-tiv] Occurring during a surgical operation
· in vitro Literally means “in glass,” referring to the tubes and glass dishes used in the laboratory. The opposite of in vivo. In research, reactions occurring in vitro might not occur in vivo and vice-versa.
· in vivo Literally means “in the living being,” referring to something being tested in humans as opposed to the laboratory. The opposite of in vitro, inaccessible [in ak ses´ sah bul] Refers to a tumor that cannot be reached during surgery without causing unacceptable neurological damage.
· incidence The number of people newly diagnosed with a specific disease or disorder during a single year.
· incision [in sih´ zhun] A cut made in the body during surgery.
· incontinent [in kon´ ti nent] Inability to control the flow of urine from the bladder and/or stool from the bowel.
· IND Investigational new drug. A drug approved by the FDA (Food and Drug Administration) for investigational use only (clinical trials).
· indolent [in´ doe lint] Slow growing.
· infiltrating Refers to a tumor that penetrates normal, surrounding tissue.
· inflammation Redness, warmth, swelling, pain and sometimes loss of function resulting from the body’s protective response to infection or a foreign object. Due to increased blood flow and an accumulation of immune cells and secretions in the area. Also called inflammatory reaction.
· informed consent The process in which a patient learns about and understands the purpose of a treatment, and then agrees to accept it (or not). In a clinical trial, this process includes a document defining how much a patient must know about the potential benefits and risks of therapy before being able to undergo it knowledgeably. Informed consent is required by federally regulated studies.
· infratentorial [in fra ten tor´ ee al] Below the tentorium. Also called the infratentorium or the posterior fossa.
· infusion [in few´ zhun] The introduction of fluids, including drugs, into a vein, over a period of time.
· integrative medicine Combines conventional medical care with complementary and/or alternative therapies. Includes chiropractic care, acupuncture, herbal medicine, massage
therapy, behavioral therapies and mind-body self care.
· intensity modulated radiotherapy See IMRT.
· interferons [in ter fear´ onz] These biological response modifiers are thought to slow tumor growth by interfering with cell division and by stimulating the production of B cells. The interferons might also be angiogenesis inhibitors. The three families of interferon, the alpha, beta and gamma, are produced naturally in the body. Commonly abbreviated IF.
· interleukins [in ter lou´ kinz] Interleukins are biological response modifiers. There are many naturally occurring interleukins, including IL-1 through IL-18, but IL-2 has been the most widely studied in cancer treatment. IL-2 stimulates the growth and activities of many immune cells that can destroy cancer cells. Commonly abbreviated IL.
· intern A medical doctor who has completed medical school and is in the first year of additional training.
· internal radiation Also called interstitial radiation therapy or brachytherapy.
· interstitial radiation therapy [in ter stish´ al] Sources of radiation energy are implanted directly into or next to a tumor. Interstitial radiation is a local therapy. Also called brachytherapy, intracavitary radiation, radiation implants, radiation seeding or radioactive pellets.
· interventricular foramen [in ter ven trik´ you lur • foe ray´ men] The opening through which cerebrospinal fluid flows from the lateral ventricles to the third ventricle. Also called the foramen of Monro.
· intra-arterial [in trah ar teer’ ee al] Injection into an artery (that supplies a tumor). Commonly abbreviated IA.
· intracavitary [in trah cav´ ih tair ee] The administration during surgery of radiation or chemotherapy directly into a tumor or the space created when the tumor was removed.
· intracerebral [in trah seh ree´ bral] Located within the cerebral hemispheres (cerebrum).
· intracranial [in trah kra´ nee al] Within the skull.
· intradural [in trah du´ ral] Within the dura mater.
· intramural research, NCI Research performed by employees of the National Cancer Institute at the National Institutes of Health. As opposed to extramural research, which is performed by scientists employed by facilities other than NCI, such as universities, private clinics and laboratories.
· intramuscular injection [in trah mus´ ku lar] Injection into a muscle. Abbreviated IM.
· intra-operative [OP-er-ah-tiv] Occurring during a surgical operation
· intraoperative radiation therapy Radiation treatment aimed directly at a tumor during surgery. Abbreviated IORT.
· intraoperative ultrasound imaging Ultrasonic waves used during surgery to determine the depth of the tumor and its diameter. Pulsed waves are sent into the brain which then reflect back to the device. The time it takes for the “echoes” to return is measured by a computer and displayed as a TV image.
· intrathecal injection [in trah thee´ kal] Injection into the subarachnoid space of the meninges. Usually done by lumbar puncture.
· intratumoral injection [in trah too more´ al] Injection into a tumor, usually performed during surgery.
· intravenous injection, IV [in trah vee´ nus] Injection into a vein.
· intraventricular injection [in trah ven trik´ u lar] Injection into a ventricle.
· intrinsic brain stem glioma [glee o´ ma] A brain stem glioma growing totally within the brain stem. These are diffuse tumors, often a fibrillary or anaplastic astrocytoma or a glioblastoma multiforme.
· invasive [in vay´ siv] Refers to a tumor that infiltrates or diffuses into healthy tissues.
· investigator A researcher in a clinical treatment study.
· investigational new drug A drug approved by the FDA (Food and Drug Administration) for investigational use only. Commonly abbreviated IND.
· ionizing radiation [eye´ on ize ing • ray dee a´ shun] The radiation used in medicine that creates ions by knocking electrons out of atoms. Ions penetrate and interfere with living tissue, causing tumor cells to die as they attempt to reproduce.
· ipsilateral [ip sah lat´ur al] Affecting the same side.
· IRB Institutional Review Board. A healthcare facility committee of scientists, doctors, clergy and consumers charged with protecting patients who take part in clinical trials. They must approve all protocols at their facility. IRBs check to see that studies are well-designed, do not involve undue risks, and include safeguards for patients.
· irradiation [ih ray dee a´ shun] Treatment by ionizing radiation, such as x-rays, or radioactive sources such as radioactive iodine seeds. Also called radiation therapy.
· isotope An unstable element that releases radiation as it breaks down. It can be used in imaging tests or as a treatment for cancer. Also called a radioisotope.