Ablation:  Removal or excision.  Ablation is usually
carried out surgically.

------------------------

Acoutstic Neuroma:  A benign tumor that may develop on the
hearing and balance nerves near the inner ear.  Can be
treated by Stereotactic RadioSurgery (SRS).

-------------------------

Adipose: Fat, but usually refers specifically to tissue
made up of fat cells, such as yellow layer of fat
beneath skin.

-------------------------

Adjuvant Chemotherapy:  Given to prevent growth of stray 
cancer cells remaining in the body after surgery or 
radiation.

-------------------------
Alopecia: Hair loss.

-------------------------

Ampulla of Vatar: An enlargement of the ducts
from the liver and pancreas where they enter 
the small intestine.


-------------------------

Angiogenesis:  The growth of blood vessels caused
by cancer. 

-------------------------

Apparent Activity:  The activity of a *bare point source*
of the same nuclide that produces the same exposure
rate at one meter as the source to be specified.  Determined
by dividing the the measured exposure rate at one m by the
exposure rate constant of the unfiltered source at one m.

-------------------------

Apodization: Literally 'removing the foot'.  A technical term
for changing the shape of a mathematical function or electrical
signal.  e.g., in optics, simulation of a gaussian laser beam 
input profile is an example of apodization

-------------------------
Arteriovenous Malformation:  A congential disorder of
blood vessels in the brain, brainstem, or spinal cord
that is characterized by a complex, tangled web of 
abnormal arteries and veins connnected by one or
more fistulas.
-------------------------

AT - Ataxia Telangiectasia:  A neurodegenerative genetic 
disease characterized by cerebellar ataxia (lack of
balance).  People with AT are predisposed to leukimia and
lymphoma and are extremely sensitive to radiation.

-------------------------

Axilla:  The cavity beneath the junction of the arm 
and the body, better known as the armpit.

-------------------------

Bleb: A bladder-like structure more than 5mm in diameter
with thin walls that may be full of fluid.  Also called
a bulla.

-------------------------
Blood:  Arterial blood transfers oxygen and nutrients
to tissues.  Venous blood transfers carbon dioxide and
metabolic by-products to lungs and kidneys.

-------------------------
Brachytherapy: Radiation treatment given by placing 
radioactive material directly in or near the target, 
which is often a tumor.

Brachytherapy for prostate cancer, for example, is 
also called interstitial radiation therapy or seed 
implantation. In brachytherapy for prostate cancer, 
radioactive seeds are implanted in the prostate. The 
seeds might be titanium-encased pellets containing 
the radioisotope iodine-125. 

"Brachy-" is Greek for "short." The opposite of 
brachytherapy is teletherapy, treatment in which the 
radiation source is at a distance from the target.

------------------------------

C1-C7:  The upper 7 cervical (neck) vertebrae.  The
top one, C1, is called the atlas.  Named after
Greek god that held earth on shoulders.

------------------------------

Carina: A ridgelike structure.

------------------------------
Cauda Equina:  Bundle of nerves at the base of 
the spinal cord.  So named because they resemble
the tail of a horse.

------------------------------

Caudal: Anatomic term meaning pertaining to the
tail or hind part.

------------------------------

Cephal - Prefix indicating the head.

------------------------------

Chondrosarcoma - Type of bone cancer.  Found mainly in 
adults.  This type of tumor forms in cartilage, the 
rubbery tissue around joints. 

-----------------------------

Coronal: A coronal plane through the body is a vertical 
plane from head to foot and parallel to the shoulders.

-----------------------------

Circle of Willis:  A joining of arteries
(anastomosis) at the base of the brain.

-----------------------------

Cytotoxic: Cell killing.

-----------------------------

Dehisce:  To burst open or gape.
A surgical wound may dehisce.

-----------------------------

De novo: New. e.g., a mutation in the DNA
can be 'de novo', meaning it has occurred
in the first generation.


-----------------------------
Dysphagia: Difficulty in swallowing.

-----------------------------

Edema:  Swelling.  e.g., tumor edema.

-----------------------------

Embolization:  A treatment that clogs small blood vessels
and blocks the flow of blood, such as to a tumor.

-----------------------------

Endogenous:  Inside.  e.g., endogenous cholesterol is that
made inside the body, as opposed to the diet.

-----------------------------

Epidemiology: The study of populations to determine disease
origin.

-----------------------------

Equivalent Uniform Dose: The homogenous dose distribution which
produces the same surviving fraction of clonogenic cells as that
obtained with an inhomogenous dose distribution.

-----------------------------

Etiology: Cause of disease.

-----------------------------

FDG - Fluoro-Deoxy-Glucose:  Active emitter in many PET scans.

-----------------------------

Fossa: An anatomical pit, groove or depression.

-----------------------------

Glioblastoma Multiforme - Type of tumor that forms from
glial (supportive) tissue in brain.  Highly malignant, 
grows quickly.


-----------------------------

Infarct: An area of tissue death due to lack of oxygen.

-----------------------------

Inferior - Below or downward. Antonym - Superior.

-----------------------------

Ipsilateral - On the same side.  The opposite of contralateral.
e.g., a tumor involving the right side of the brain may affect
vision ipsilaterally (i.e., in the right eye).

-----------------------------

Glioma: A brain tumor that begins in glial or supportive 
cell in the brain.  Malignant gliomas are the most common
from of cancer in the central nervous system (brain and
spinal cord) and often have a poor prognosis.

-----------------------------

Gray - Symbol: Gy.  The derived SI unit of 
absorbed dose of ionizing radiation and of specific 
energy imparted.  It is equal to an absorption
or delivery of one joule per kilogram of irradiated 
material.  It replaces the rad.  1 gray = 100 rad.

-----------------------------

Histology - The study of form of structures seen under
the microscopy. e.g., from a biopsy.

---------------------------

Hemiparesis - Weaknes on one side of the body.

---------------------------
Hounsfield Unit: Units of density for CT numbers.  
-1000HU = air, 0HU = H2O, +1000HU = bone. 
So a change of 1HU corresponds to a change of
0.1% of attenuation coefficient between water
and air.

---------------------------

Ilium:  The upper part of the bony
pelvis that forms the receptacle of
the head of the femur at the hip 
joint.

---------------------------
In situ:  In the normal location.  An "in situ" 
is one that is confined to its site of origin and 
has not invaded neighboring tissue or gone elsewhere
in the body.

----------------------------

In vivo:  In the living organism.

---------------------------

In vitro:  In the laboratory.

---------------------------

Intrahepatic:  Within the liver.

---------------------------

Isocenter:  A point of intersection of the collimator
axis and the gantry axis of rotation.

-----------------------------
KERMa: Acronym - Kinetic Energy Released in the 
Medium.  The quotient of dE_tr by dm.  The unit for 
kerma is the same as for dose, i.e., J/kg.

--------------------------

L1-L5:  The five lumbar vertebrae situated between the
thoracic vertebrae and the sacral vertebrae in the spinal
column.

--------------------------

Longitudinal Study: A study done over the passage of
time.

--------------------------

Macula:  Spot.  In the retina, the macula is the spot
where the center of images are focused.

--------------------------

Medial: The side of the body or body part that is nearer 
to the middle or center of the body.  Antonymn - lateral.

--------------------------

Mediastinum: The area between the lungs.  The organs in this
area include the heart and its large veins and arteries,
the trachea, the esophagus, the bronchi and lymph nodes.

--------------------------
Metastasis: The very important process by which 
cancer spreads from one part of the body to another, 
the way it travels from the place at which it first 
arose as a primary tumor to distant locations in the body. 

The term "metastasis" also applies to a tumor that 
crops up by this process due to the spread of the 
primary tumor. For example, someone with melanoma 
may have a metastasis in their brain. And a person 
with colon cancer may fortunately show no metastasis. 

Cells that metastasize are basically of the same 
kind as those in the original tumor. So, if the cancer 
arose in the lung and metastasized to the 
liver, the cancer cells growing in the liver 
are lung cancer cells. 

The ancient Greeks used the word metastasis to mean 
"removal from one place to another." The plural of 
"metastasis" is "metastases."

----------------------------

Morbidity: Illness, disease.

---------------------------

Mortality: A fatal outcome or, in one word, death.  
The word 'mortality' is derived from 'mortal' which 
came from the Latin 'mors'(death).

--------------------------

Murine: Rat or mice.

--------------------------
Neoadjuvant Chemotherapy:  May be used to shrink a
large tumor prior to surgical resection, or to be
treated more effectively with radiation.

--------------------------

Neoplasia:  The process of abnormal and uncontrolled
growth of cells.  The product of neoplasia is a neoplasm
(a tumor).

--------------------------

Nidus: Latin word for nest.  Any structure that resembles
a nest in appearnce.  e.g., AVM.  pl - nidi.

--------------------------
NTCP: Normal Tissue Complication Probability.

--------------------------

Occult: Hidden.

--------------------------

Optic Chiasm:  Crossing of the optic nerves.

--------------------------

Orthotopic:  In the normal or usual position.

--------------------------
Os:  The mouth or upper opening of the digestive tract.
Any opening or aperature in the body.

--------------------------
Osseous - Having to do with the bone, consisting of 
bone or resembling bone. From "os" which is a synonym 
for "bone."  The Latin word "os" means "bone"
as does the related Greek word "osteon."

---------------------------

Palliative care: 1) Medical or comfort care that 
reduces the severity of a disease or slows its progress 
rather than providing a cure.  For incurable diseases, 
in cases where the cure is not recommended due to other 
health concerns, and when the patient does not wish to pursue
a cure, palliative care becomes the focus of treatment.  
For example, if surgery cannot be performed to remove a tumor, 
radiation treatment might be tried to reduce its rate of 
growth, and pain management could help the patient manage 
physical symptoms. 2) In a negative sense, provision
only of perfunctory health care when a cure is possible.

----------------------------

Parenchyma: Key elements of an organ to its functioning,
as distinct from the capsule that encompasses it, or other
supporting structures.  e.g., the parenchyma of the testis
are the seminferous tubules.

----------------------------
Parotid gland:  The largest of the three major salivary 
glands, it is located in front and below the ear and behind 
the jaw bone.  The other two glands are the submandibular
(submaxillary) and sublingual.

----------------------------

Perfusion:  Flowing over or through.  Blood flow through 
the organs and tissues. 

----------------------------
Plexus: Network or tangle of lymphatic
vessels, nerves or veins.  e.g., brachial
plexus network of nerves leading to
the arm.

----------------------------
Portal Vein:  A large vein that caries blood from the
stomach and intestines to the liver.

----------------------------

Prone - Lying face downward.

----------------------------

Prophylactic - Prevenative measure.

----------------------------

Resection - Surgical removal of part of an organ.

----------------------------

Restenosis - reclosing of an artery after, e.g., angioplasty.

----------------------------

S1-S5:  The five sacral vertebrae situated below the 
lumbar vertabrae and above the coccyx, which is the
lowest segment of the vertebral column.

----------------------------

Sacrum:  The large heavy bone at the base of the
spine made up of fused sacral vertebra.  Located 
between the lumbar vertebrae and the coccyx.  Roughly
triangular in shape and makes up back wall of pelvis.
Wider in females.

----------------------------
Sagittal: A vertical plane passing through the body 
which divides it into left and right sides.

----------------------------

Sarcoma: One of a group of tumors usually arising
from connective tissue.  Most sarcomas are malignant.
Many types are named after the type of cell, tissue
or structure involved such as angiosarcoma, chondrosarcoma,
etc.

----------------------------

Seminal Vesicle:  Structure in male about 5cm long
and located behind bladder and above prostate.
Contributes fluid to the ejaculate.

----------------------------

Sensitivity:  (true-positives)/(true-positives + false-negatives).
A number close to 1 is desirable.

----------------------------

Sinogram: Image representation of raw data obtained when
projection reconstruction is used.

----------------------------

Specificity: (true-negatives)/(true-negatives + false-positives).
A number close to 1 is desirable.

----------------------------

Squamous cell carcinoma: Cancer that begins in squamous 
cells -- thin, flat cells that look under the microscope 
like fish scales. The word "squamous" came from the Latin 
squama meaning "the scale of a fish or serpent." 

Squamous cells are found in the tissue that forms the 
surface of the skin, the lining of the hollow organs 
of the body, and the passages of the respiratory and 
digestive tracts so squamous cell carcinomas may 
arise in any of these tissues. 

----------------------------

Stereotactic - Precise positioning in three
dimensional space.  e.g., a biopsy, surgery or
radiotherapy can be performed stereotactically.

-------------------------------

Stereotactic radiotherapy: Radiation therapy in which a 
number of precisely aimed beams of ionizing radiation 
coming from different directions meet at a specific point, 
delivering the radiation treatment to that spot.

----------------------------

Sulcus - Any of the narrow fissures separating 
convolutions of the brain. pl - sulci

----------------------------

Superior - Above. Antonym - Inferior.

----------------------------

Supine - Lying on the back.

----------------------------

Surrogate Marker:  An indirect indicator of something, such
as measuring viral load to assess the treatment effect of
a drug.

---------------------------

Synovectomy - Removal of the synovial membrane located
in joints.  Treatment for arthritis.

---------------------------------------------------------

Syncope - fainting.

---------------------------------------------------------

T1-T12:  The twelve thoracic vertabrae situated between
the cervical (neck) vertabrae and the lumbar vertabrae.
They provide attachment points for the ribs.

---------------------------------------------------------

Vaginal Fornix:  The anterior and posterior recesses into which
the upper vagina is divided.  Fornix is Latin for vault.
Ovoids often are placed into these during Tx for cervical
cancer.

---------------------------------------------------------

Wilms Tumor: A cancer of the kidney.  One of the most important
malignancies of childhood, due to loss or inactiviation of a
tumor suppressor gene called WT1 on chromosome 11.

---------------------------------------------------------

Xenograft: A surgical graft from one species to an unlike
species.  e.g., from a human breast tumor to mice.

---------------------------------------------------------


I obtained many of the above definitions at MedTerms.com.


 

Note:  If a mistake or inconsistency is noticed here, please 
email me . 


Last updated on 4/4/06.