| SolveYourProblem
Article Series: Cancer
Help Me Understand Cancer
6
Types of External Cancer Radiation Therapies
Going through external beam radiation therapy
is a lot like getting a routine x-ray: You feel nothing, and
you see nothing. You do, however, hear something - the buzzing
and clicking of the machine that delivers the radiation to
the cancer site.
Most often, the machine used during external radiation therapy
is a linear accelerator (LINAC for short). A time-tested machine
that is updated as improvements are developed, the LINAC can
deliver beams of both low and high-energy photons and electrons.
Other machines used in external beam radiation therapy include
orthovoltage x-ray machines and cobalt-60 machines, which deliver
low-energy beams.
Several different types of external beam radiation are available.
Keep in mind that the necessary equipment is not always available
in smaller hospitals. To get the treatment you need, you may
have to travel to a medical center that has the up-to-date,
high-tech equipment required.
1.
Photon/electron Radiation Therapy: The most common form
of radiation therapy in use is high-energy photon (x-ray) beam
radiation, which is used to destroy or shrink tumors and to
destroy any cancer cells in an area where a tumor has been
removed. Most cancers are treated with high-energy photon radiation.
Low-energy radiation is used to treat surface tumors.
Electrons are charged particles used to treat more superficial
tumor sites, such as lymph nodes in the neck; to boost treatment
of a breast cancer site; or to treat skin cancers. Electron
beams have different energies and must be carefully chosen
for the appropriate depth of the cancer being treated. Often,
patients are treated with a combination of photons (x-rays)
and electrons (accelerated charged particles).
2.
Three-Dimensional Con Format Radiation Therapy (3D-CRT): Three-dimensional conformal radiation therapy calls on computers
and computer-assisted tomography scans (also know as CT or
CAT scans), along with magnetic resonance imaging scans (MR
or MRI scans), to create a three-dimensional representation
of a tumor and the surrounding organs. Tools called multileaf
collimators, or blocks, match the radiation beams to the size
and shape of the tumor. This allows for less radiation exposure
to nearby normal tissue.
3.
Intensity modulated Radiation Therapy (1MRT): This type of radiation therapy is a form of 3D-CRT that breaks
the radiation
beam into many small "beamlets," with individually
adjusted levels of intensity. Sometimes, IMRT can be used to
deliver a higher dose of radiation directly to the tumor while
limiting radiation received by normal tissues. This currently
is the most precise, cutting-edge form of external radiation,
and it requires meticulous planning and quality assurance on
the part of the radiation oncologist, physicist, dosimetrist,
and radiation therapists.
4.
Proton Beam Radiation Therapy: Proton beam therapy uses
protons (charged particles), rather than x-rays, to treat cancer.
Proton therapy provides a sharper beam, which may be useful
in treating lesions close to the spinal cord, for example.
However, there's a price to pay for that precision: potentially
intensified side effects. This therapy is very costly, and
few proton beam therapy machines are available in the United
States.
5.
Neutron Beam Radiation Therapy: Some tumors that are radio-resistant,
or difficult to kill with conventional radiation therapy, can
be treated with neutron beam therapy. This type of therapy
occasionally is used to treat some inoperable tumors, though
most often such tumors are treated with radiation therapy using
photon (x-ray) and electron radiation therapy.
6.
Stereotactic Radiation Therapy: In Stereotactic radiation
therapy, high doses of radiation are focused on a small area,
no larger than 2 to 3 centimeters. Also, many beams of high-dose
radiation converge on the tumor from different directions.
This therapy is often used to treat small tumors in the head,
brain, lungs, and other sites. # # # # #
SolveYourProblem.com
: 2006
> Home > Cancer Articles
: Main Page
|
