may hear or read the following words in relation to radiation therapy.
These definitions are meant to help you understand the terms, but
are not intended as a substitute for the explanations you receive
from the Therapy Team:
/ G-L / M-R / S-Z
therapy: Treatment that is used in addition to primary therapy
to enhance it. Radiation therapy or chemotherapy is often used as
an adjuvant to surgery.
Alopecia: Hair loss
Anesthesia: The loss
of feeling or sensation as a result of drugs. General anesthesia
causes temporary loss of consciousness (“puts you to sleep”).
Local or regional anesthesia numbs only a certain area.
BAT (B-mode Acquisition and
Targeting): A device designed to maximize the precision of
external beam radiation by using ultrasound to locate and visualize
A benign tumor is an abnormal but noncancerous growth that doesn’t
spread to other places in the body.
Biopsy: A surgical
procedure in which the tissue sample is obtained for study and identification
by a pathologist.
Biopsy proven: A term
describing disease that has been identified by a pathologist who
examined a tissue sample.
Brachytherapy: A type
of radiation therapy in which radioactive material is placed permanently
or temporarily on the body, within a cancerous growth, or within
a body cavity near the tumor.
Brachytherapy, High Dose
Rate (HDR): A temporary type of brachytherapy in which the
highly active radioactive source is used to deliver radiation into
the body in a short period of time.
Brachytherapy, Low Dose Rate
(LDR): Brachytherapy in which sources are left in place for
the duration of treatment. This includes temporary LDR in which
patients are hospitalized for several days of temporary brachytherapy.
It also includes permanent LDR in which sources are permanently
Cancer: A term used
to describe many different diseases, all of which are characterized
by perpetual abnormal cell growth and division, infiltrating locally
by invasion and remotely by metastasis.
Carcinogen: A substance
known to cause cancer.
Catheter: A thin,
flexible tube through which fluids or other materials enter or leave
of cancer with drugs given intravenously or orally.
Cobalt 60: A radioactive
isotope used for gamma ray external-beam radiation therapy. This
type of treatment has mainly been replaced by linear accelerators.
A type of radiation therapy in which multiple beams are shaped and
angled to conform to the tumor's height, width, and depth, reducing
the radiation delivered to normal tissues.
Normal tissues or organs near the tumor whose preservation limits
the amount of radiation that can be administered.
CT scan (or CAT scan):
Computed tomography scan. A series of detailed pictures of areas
inside the body taken from different angles. The pictures are created
by a computer linked to an x-ray machine.
Cyclotron: A charged-particle
accelerator used in cancer radiation therapy for generating proton
and neutron beams.
Definitive: A term
used to describe radiotherapy meant to eradicate all disease.
A physician who specializes in administering and interpreting such
tests as X-ray studies, computerized tomography (or CAT) scans,
or ultrasonography studies.
Dietitian: A specialist
in proper nutrition.
who calculates radiation therapy doses.
Electron beam: Radiation
therapy made up of a stream of high-energy electrons. Generally
this is used to treat superficial tumors.
External beam radiation therapy
(or external radiation): Treatment in which the radiation
source is at a distance from the body.
practice of dividing a determined dose of radiation into fractions,
usually administered once or twice daily.
A type of stereotactic radiosurgery using multiple cobalt-60 sources.
Gamma rays: A type
of electromagnetic radiation emitted from a natural radiation source,
i.e. cobalt 60.
Gleason score: A system
of grading prostate cancer cells describing how aggressive the cancer
appears. It is used to determine the best treatment and to predict
how well a person is likely to respond to treatment. The lower the
Gleason score, the closer the cancer cells are to normal cells,
the higher the Gleason score, the more abnormal the cancer cells.
Gray: A measure of
A method of dosing radiation therapy in which small amounts of radiation
are administered more frequently than once per day.
Image-guided radiation therapy
(IGRT): A method of visualizing and localizing the tumor
before each treatment. The patient can be scanned and the tumor
located in 3D space immediately before treatment so that corrections
can be made for patient movement and setup errors. See BAT and Tomotherapy.
An apparatus that prevents movement in the treatment position.
Implant: The process
by which a radiation source is placed in or near a cancer.
therapy (IMRT): A highly sophisticated computer controlled
method of varying the intensity and shape of the radiation beam
to match the shape of the tumor while protecting surrounding normal
Internal radiation therapy:
A type of therapy in which a radioactive substance is placed into
or close to the area needing treatment. Also called brachytherapy,
implant radiation or interstitial radiation therapy.
A radioactive source placed inside a body cavity, such as the cervix
Radiation therapy administered during a surgical operation.
Ionizing: Term used
to describe electromagnetic radiation capable of producing ionization
in passage through matter.
Iridium: A radioactive
isotope used in brachytherapy.
Karnofsky Performance Status
score: A rating from 0 to 100 indicating ability to function
Linac: see linear
A machine used to produce X rays or electrons used in radiation
describing a cancerous growth with a tendency to invade and destroy
nearby tissue and spread to other parts of the body.
A physician who specializes in treating cancer with chemotherapy.
Metastasis: The spread
of disease from one site in the body to one or more unconnected
sites. Tumors formed from cells that have spread are called “secondary
tumors” and contain cells that are like those in the original
tumor. The plural form of metastasis is metastases.
Mets: see Metastasis
Involving two or more medical specialties.
an attachment to the linear accelerator that shapes the radiation
to conform to the tumor or treatment area.
Neutron: A neutral,
uncharged subatomic particle used in cancer radiation treatment.
Oncologist: A physician
who specializes in treating cancer.
Palliation (or palliative
care): Therapy not meant to cure but to ease symptoms.
Identification and matching of ideal treatment field with the actual
treatment field using radiographic images or electronic portal imaging
Port Film: An x-ray
used to verify the position and accuracy of the treatment beam.
Proton therapy: Radiation
therapy with positively charged particles accelerated into beams.
Quality of life: Subjective
sense of well-being.
A physician whose specialty is treating cancer with radiation.
A person who usually holds an advanced degree in physics who ensures
that the machines used in radiation therapy administer the correct
amount of radiation to patients and who, with the radiation oncologist,
calculates the proper dose for individual patients.
A person specially trained and licensed to administer radiation
Radiation therapy (also called
Radiotherapy): An intervention to eradicate cancer cells
that employs high-energy photon, electron, neutron, and proton beams
for treatment from sources outside the body and radioactive implants
for treatment within the body.
Radiation therapy nurse:
A registered nurse who has extensive training in oncology and radiation
drug used to protect cells from radiation.
drug used to sensitize cells to radiation's effects.
Stereotactic radiation therapy.
Radioactive pellets, approximately the size of a grain of rice,
that are used in brachytherapy.
Simulation: The process
of locating and marking the treatment field to be targeted in radiation
Stage: The extent
of a cancer within the body, especially whether the disease has
spread from the original site to other parts of the body. See Tumor
Stereotactic radiation surgery:
The technique used to deliver a single high-dose of radiation to
a small focus of disease usually within the brain.
A type of plastic surgery that restores the shape of a body area
Target volume: The
area meant to receive the radiation; usually areas containing known
or suspected tumors or suspected cancer cells.
Three-dimensional (3D) conformal
radiation therapy: See Conformal therapy
Tomotherapy: The newest
and most precise radiation therapy technology. Physicians can take
images of a patient's body and treat the patient during the same
session. Corrections can be made on the spot for patient movement.
Radiation is delivered from all angles and modulated constantly
to give low doses to certain areas of the body and higher doses
to others. See IGRT.
Tumor: An abnormal
mass of tissue that results from excessive cell division. Tumors
perform no useful body function. They may be benign (not cancerous)
or malignant (cancerous).
Tumor staging: This
is an important step in the management of cancer. Typically, several
tests are performed to determine 3 things. The first part is to
quantify the size and extent of a primary cancer. The second is
to determine whether nearby lymph nodes are involved by the cancer.
The third is to check whether cancer has spread through the blood
stream to other parts of the body. Using this information, people
with cancer are assigned a stage. This helps to determine the best
course of treatment and it also predicts the response to treatment.
Each type of cancer has a specific staging system.
Treatment field: The
area to be treated by radiation therapy. The area exposed to a single
Tumor: An abnormal
lump or mass of tissue. Tumors are either benign (noncancerous)
or malignant (cancerous).
Ultrasound: A test
that bounces sound waves off tissues and internal organs and changes
the echoes into sonograms (pictures).
X rays: High-energy
electromagnetic radiation, photons.