The radiation used in radiation therapy can come from a
variety of sources. Your doctor may choose to use x-rays,
or an electron beam. Choosing which type of radiation to
use depends on what type of cancer you have and on how deep
into your body the doctor wants the radiation to penetrate.
High-energy radiation is used to treat many types of cancer.
Low-energy x-rays are used to treat some kinds of skin diseases.
After a physical exam and a review of your medical history,
the radiation oncologist may need to do some special planning
to pinpoint t he treatment area. In a process called simulation,
you will be asked to lie very still on a table while the
radiation therapist uses a special x-ray machine to define
your treatment port or field. For planning of three-dimensional
conformal therapy, a CT scanner is used for this process.
This is the exact place on your body where the treatment
will be aimed. You may have more than one treatment port.
Simulation may take from a half-hour to about 2 hours.
The radiation therapist often will mark the treatment port
on your skin with tiny dots of colored, semipermanent ink
to outline the treatment area. Be careful when you bathe
because the marks must not be washed off until all
of your treatment is over. If they start to fade, tell the
therapist who will darken them so that they can be seen easily.
Do not try to draw over faded lines at home unless
they will be completely gone before your next visit. If you
do replace the marks, be sure to tell the therapist at your
next visit. Using the information from the simulation, other
tests, and your medical background, your doctor will meet
with the radiation physicist and the dosimetrist. Your doctor
then decides how much radiation is needed, how it will be
delivered, and how many treatments you should have. This
process often takes several days.
After you have started the treatments, your doctor will
follow your progress, checking your response to treatment
and your overall well-being at least once a week. The treatment
plan may be revised by your doctor, if needed. It's very
important that you have all of your scheduled treatments
to get the most benefit from your therapy. Unnecessary delays
can lessen the effectiveness of your radiation treatment
Radiation therapy usually is given 5 days a week for 6 or
7 weeks. When radiation is used for palliative care, the
course of treatment lasts for 2 to 3 weeks. These types of
schedules, which use small amounts of daily radiation, rather
than a few large doses, help protect normal body tissues
in the treatment area. Weekend rest breaks allow normal cells
to recover. The total dose of radiation and the number of
treatments you need will depend on the size and location
of your cancer, type of tumor, your general health, and any
other treatments you're receiving.
Before your treatment is given, you may need to change into
a hospital gown or robe. It's best to wear clothing that
is easy to take off and put on again. In the treatment
room, the radiation therapist will use the marks on your
skin to locate the treatment area. You will sit in a special
chair or lie down on a treatment table. For each external
radiation therapy session, you will be in the treatment room
about 15 to 30 minutes, but you will be getting your dose
of radiation for only about 1 to 5 minutes of that time.
Receiving external radiation treatments is painless, just
like having an x-ray taken.
The radiation therapist may put special shields (or blocks)
between the machine and certain parts of your body to help
protect normal tissues and organs. There might also be plastic
or plaster forms to help you stay in exactly the right place. You
will need to remain very still during the treatment so that
the radiation reaches only the area where its needed and
the same area is treated each time. You don't have to
hold your breath--just breathe normally.
The radiation therapist will leave the treatment room before
the machine is turned on. The machine is controlled from
a small area that is nearby. You will be watched on a television
screen or through a window in the control room. Although
you may feel alone, keep in mind that you can be seen and
heard at all times by the therapist who can talk with you
through a speaker.
The machines used for radiation treatments are very large,
and they make noises as they move around to aim at the treatment
area from different angles. Their size and motion may be
frightening at first. Remember that the machines are being
moved and controlled by your radiation therapist. They are
checked constantly to be sure they're working right. If you
are concerned about anything that happens in the treatment
room, ask your therapist to explain.
You will not see or hear the radiation, and, most likely,
you won't feel anything. If you do feel ill or very uncomfortable
during the treatment, tell your therapist at once. The machine
can be stopped at any time.
Radiation is usually given once a day in a dose that is
based on the type and location of the tumor. In hyperfractionated
radiation therapy, the daily dose is divided into smaller
doses that are given more than once a day. If more than one
treatment is given per day to an area, the treatments usually
are separated by 4 to 6 hours. Doctors are studying hyperfractionated
therapy to see if it is equally or even more effective than
once-a-day therapy. Early results in certain tumors are encouraging,
and hyperfractionated therapy is becoming a more common way
to give radiation treatments.
External radiation therapy does not cause your body
to become radioactive. There is no need to avoid being with
other people because of your treatment. Even hugging, kissing,
or having sexual relations with others poses no risk to them
of radiation exposure.
Side effects of radiation therapy most often are related
to the area that is being treated. Your doctor and nurse
will tell you about the possible side effects and how you
should deal with them. You should contact your doctor or
nurse if you have any unusual symptoms during your treatment,
such as coughing, sweating, fever, or unusual pain. Most
side effects that occur during radiation therapy, although
unpleasant, are not serious and can be controlled with medication
or diet. They usually go away within a few weeks after treatment
ends. However, some side effects can last longer. Many patients
have no side effects at all. In another section "Managing
Side Effects," you will find advice on how to cope with
the side effects that might occur during and after your therapy.
Throughout your treatment, your radiation oncologist will
regularly check on the effects of the treatment. You may
not be aware of changes in the cancer, but you probably will
notice decreases in pain, bleeding, or other discomforts
you may have had, especially after your treatment is completed.
You may continue to notice more improvements with time. Your
doctor probably will recommend some tests to be sure that
the radiation is causing as little damage to normal cells
as possible. You may have routine blood tests to check the
levels of white blood cells and platelets, which may be lower
than normal during treatment.
Each patient's body responds to radiation therapy in its
own way. That's why the doctor must plan, and sometimes adjust,
your treatment just for you. In addition, your doctor or
nurse will give you advice for caring for yourself at home
that is specific for your treatment and the side effects
that might result. Nearly all cancer patients receiving radiation
therapy need to take special care of themselves to protect
their health and help the treatment succeed. Some guidelines
to remember are given below:
Be sure to get plenty of rest. Sleep as often as you
feel the need. Your body will use a lot of extra energy
over the course of your treatment, and you may feel very
tired. In fact, fatigue may last for 4 to 6 weeks after
your treatment is finished.
Good nutrition is a must. Try to eat a balanced diet
that will prevent weight loss. For patients who have
problems with eating or diet planning, the section titled "Managing
offers practical tips.
Avoid wearing tight clothes such as girdles or closefitting
collars over the treatment area. It's best to wear older
garments that feel comfortable and that you can wash
or throw away if the ink marks rub off on them.
Do not use any soaps, lotions, deodorants, medicines,
perfumes, cosmetics, talcum powder, or other substances
in the treated area without talking with your doctor.
Wear loose, soft cotton clothing over the treated area.
Do not starch your clothes.
Do not rub or scrub treated skin.
Do not use adhesive tape on treated skin. If bandaging
is necessary, use paper tape. Try to apply the tape outside
of the treatment area.
Do not apply heat or cold (heating pad, ice pack, etc.)
to the treatment area. Even hot water can hurt your skin,
so use only lukewarm water for bathing the treated area.
Use an electric shaver if you must shave the
area-- but only after checking with your doctor or nurse.
Do not use a preshave lotion or hair remover products.
Protect the area from the sun. If possible, cover treated
skin (with light clothing) before going outside. Ask
your doctor if you should use a lotion that contains
a sunblock. If so, use a PABA sunscreen or a sunblocking
product with a protection factor of at least 15. Reapply
the sunscreen often, even after your skin has healed
following your treatment. Continue to protect your skin
from sunlight for at least 1 year after radiation therapy.
Be sure your doctor knows about any medicines you are
taking before starting treatment. If you need to start
taking any medicines, even aspirin, let your doctor know
before you start.
Ask your doctor, nurse, or radiation therapist any questions
you have. They are the only ones who can properly advise
you about your treatment, side effects, at-home care,
and any other medical concerns you may have.
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