Brain Tumor Glossary of Terms

Easily explore the meaning of hundreds of medical terms or words, many directly used in brain tumor-related terminology.

i
Idiopathic

Describes a disease of unknown cause.

Imaging

In medicine, a process that makes pictures of areas inside the body. Imaging uses methods such as x-rays (high-energy radiation), ultrasound (high-energy sound waves), and radio waves.

Immune Response

The activity of the immune system against foreign substances (antigens).

Immune System

The complex group of organs and cells that defends the body against infections and other diseases.

Immunity

The condition of being protected against an infectious disease. Immunity can be caused by a vaccine, previous infection with the same agent, or by transfer of immune substances from another person or animal.

Immunotherapy

Treatment to boost or restore the ability of the immune system to fight cancer, infections, and other diseases. Also used to lessen certain side effects that may be caused by some cancer treatments. Agents used in immunotherapy include monoclonal antibodies, growth factors, and vaccines. These agents may also have a direct antitumor effect. Also called biological response modifier therapy, biological therapy, biotherapy, and BRM therapy.

In Situ

In its original place. For example, in carcinoma in situ, abnormal cells are found only in the place where they first formed. They have not spread.

In Vitro

In the laboratory (outside the body). The opposite of in vivo (in the body).

In Vivo

In the body. The opposite of in vitro (outside the body or in the laboratory).

Indication

In medicine, a sign, symptom, or medical condition that leads to the recommendation of a treatment, test, or procedure.

Informed Consent

A process in which a person is given important facts about a medical procedure or treatment, a clinical trial, or genetic testing before deciding whether or not to participate. It also includes informing the patient when there is new information that may affect his or her decision to continue. Informed consent includes information about the possible risks, benefits, and limits of the procedure, treatment, trial, or genetic testing.

Intensification Therapy

Treatment that is given after cancer has disappeared following the initial therapy. Intensification therapy is used to kill any cancer cells that may be left in the body. It may include radiation therapy, a stem cell transplant, or treatment with drugs that kill cancer cells. Also called consolidation therapy and postremission therapy.

Intensity Modulated Radiation Therapy (IMRT)

In IMRT, the beam intensity is varied across the treatment field. Rather than being treated with a single, large, uniform beam, the patient is treated instead with many very small beams; each can have a different intensity. By cross firing the tumor with these beams, the physician delivers a relatively uniform radiation dose to the tumor, but protects sensitive, surrounding tissue from high-dose radiation.

Interstitial Chemotherapy

Performed during surgery when a chemotherapy-soaked, biodegradable wafer is placed into the tumor resection cavity in a controlled-release fashion.

Intraaterial chemotherapy

Uses catheter tubes for high-dose delivery of chemotherapy in the brain's arteries.

Intracranial Tumor

A tumor that occurs in the brain.

Intraspinal

Within the spine (backbone).

Intrathecal

Describes the fluid-filled space between the thin layers of tissue that cover the brain and spinal cord. Drugs can be injected into the fluid or a sample of the fluid can be removed for testing.

Intrathecal chemotherapy

Delivers medication directly into the spinal fluid.

Invasive Cancer

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

Invasive Procedure

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

Investigational Agent

A substance that has been tested in a laboratory and has gotten approval from the U.S. Food and Drug Administration (FDA) to be tested in people. An investigational agent may be approved by the FDA for use in one disease or condition but be considered investigational in other diseases or conditions. Also called experimental drug and investigational drug.

Investigational Drug

A substance that has been tested in a laboratory and has gotten approval from the U.S. Food and Drug Administration (FDA) to be tested in people. An investigational drug may be approved by the FDA for use in one disease or condition but be considered investigational in other diseases or conditions. Also called experimental drug and investigational agent.

Investigator

A researcher in a clinical trial or clinical study.

IRB

A group of scientists, doctors, clergy, and consumers that reviews and approves the action plan for every clinical trial. There is an IRB at every health care facility that does clinical research. IRBs are designed to protect the people who take part in a clinical trial. IRBs check to see that the trial is well designed, legal, ethical, does not involve unneccesary risks, and includes safeguards for patients. Also called Institutional Review Board.

Irradiated

Treated with radiation.

Irreversible Toxicity

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

IV

Into or within a vein. IV usually refers to a way of giving a drug or other substance through a needle or tube inserted into a vein. Also called intravenous.