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Radiation Treatment Facts
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Disclaimer: The information below is intended to only serve as a general
reference regarding radiation therapy. Any information presented here should
not substitute for a consultation with a trained radiation oncologist.
General Questions Regarding Radiation Therapy:
Who will give me my radiation treatments? The administration of radiation treatments is a complex process that requires a team of professionals whose specific roles are described below: The Radiation Oncologist is a physician who specializes in the use of radiation therapy to treat cancer and other diseases and serves as the leader of the team, and directs all aspects of the patients radiation treatments. The Radiation Oncologist will be referred to henceforth as "your doctor". The Radiation Physicist has a Masters or PhD degree in medical physics and supervises the technical aspects of radiation treatments. The Dosimetrist calculates the dose of radiation given to the patient, often using high-end computer technology, and is supervised by both the Radiation Oncologist and Radiation Physicist.
The Radiation Therapist operates the machine that administers radiation therapy
on a daily basis. Your doctor will not actually administer your radiation
treatments on a daily basis, but he or she will actively oversee all aspects of
your treatment. You will see your doctor once a week in the clinic during you
treatment as well.
How does radiation treat cancer?
Radiation treats cancer by damaging cancerous cells, causing them to die when
they attempt to divide. As a result, it can often take a number of weeks to
see maximal regression of tumors after a completed course of radiation therapy.
Radiation only treats tumors that are either within the high-dose region of
the radiation beam, or are close to an implanted radioactive source.
How are radiation treatments given?
Radiation treatments are often given using a high energy x-ray machine known as
a linear accelerator, this is known as "external beam radiation therapy" or
"teletherapy". A linear accelerator is able to rotate around a patient while
they lie on a treatment table known as the "couch". In addition, radiation
treatment are sometimes given by inserting a radioactive source either into,
or close to, the tumor. This type of radiation treatment is known as
"brachytherapy".
What are the side effects of radiation treatments?
The side effects of radiation treatments are usually limited to the local area
where the radiation treatment is given. This can include skin irritation and
variable hair loss. Nausea and diarrhea can often result when radiation
treatments are given to the abdomen or pelvis. In some cases, radiation
treatment may have long term side effects as well, but these are usually
outweighed by the benefits that radiation therapy provides in treating cancer
and other diseases. Your doctor will discuss the specific side effects of your
treatment with you.
It it safe for me to be around family and friends during my radiation treatments?
If radiation treatments are given using
"external beam radiotherapy"
, no radiation remains inside the patient after each treatment session, thus it
is completely safe to be around family and friends during a course of this type
of radiation treatment. In addition, some radiation treatments are given by
temporarily inserting a radioactive source into or close to the tumor and then
removing it at the end of each treatment session. In this case as well, no
radiation remains in the patient after the treatment session and it is safe to
be around others. The only case in which radiation remains inside the patient
after treatment is when radioactive sources or seeds are permanently inserted
into the tumor, as is often done for prostate cancer. Nevertheless, the
radiation dose to other people even in this case is often negligible. Your
doctor will discuss any precautions you may need to take in cases where
radiative seeds are permanently implanted into a tumor.
How long do radiation treatments take?
The actual time required to adminster
"external beam radiotherapy"
ranges from five to forty-five minutes, depending on the complexity of the
treatment, the actual radiation beam is only on for a fraction of this time.
The majority of the time that the patient spends on the radiation treatment
table involves the verification of proper patient positioning.
Can radiation be used to treat diseases other than cancer?
Radiation therapy is often used to treat diseases other than cancer. Most
recently, radiation has been shown to reduce the rate of restenosis
("re-blockage") in patients who have had a narrowing of their coronary arteries
opened by an angioplasty. In this case, a radioactive source is temporarily
inserted into the coronary artery during a cardiac catheterization. In
addition, radiation can be used to treat a benign condition of the eye known as
"pterygium" and is often used to prevent abnormal bone growth after hip
replacement. Furthermore, radiation can be used to prevent the development of
agressive scar formations known as "keloids" that affect some individuals.
What is the difference between surgery, radiation therapy, and chemotherapy? In general, many cancers can be thought of as diseases that have three different stages. The earliest stage can be thought of as localized cancer. In this case, the cancer is confined to only one area or organ of the body with no evidence of tumor spread to the lymph nodes. The second stage occurs when tumor cells have spread from the original tumor to the surrounding lymph nodes, but have not spread to other organs in the body. The third stage occurs when cancer cells have spread from the original tumor to other organs of the body. Cancer is often treated differently depending on the stage of disease. Surgery is often used in cancer treatment to remove a tumor in the operating room, in some selected cases of cancer, this may be the only therapy that is needed. However, in some cases, microscopic cells are left behind in the patient at the time of surgery, these cells can grow - causing the tumor to recur. Radiation therapy can be used as an alternative to surgery or is often used after surgery to sterilize the microscopic cancer cells that may have been left behind at the time of surgery. In addition to treating cancer cells in the tumor, radiation therapy can also be used to treat microscopic cancer cells that may have spread to surrounding lymph nodes. It should be noted that radiation therapy can only kill cancer cells that are located within the radiation beam.
Chemotherapy is also used to treat microscopic cancer cells, either those in
lymph nodes, or those that have traveled to other distant sites of the body.
Since chemotherapy is given via the bloodstream, it can potentially kill cancer
cells that are located far away from the original tumor.
What is "3D Conformal" Radiotherapy?
"3D Conformal" radiation therapy is a type of radiation treatment in which the
radiation beam is precisely shaped to conform to the shape of the tumor, thus
potentially sparing other normal tissues that many lie close by. This
technology requires the use of high powered computers to calculate the
radiation dose. All of the facilities within our practice have 3D Conformal
radiotherapy available.
What is "Intensity Modulated Radiotherapy" (IMRT)?
"Intensity Modulated Radiotherapy" or "IMRT" is simply a somewhat more complex
form of
3D Conformal Radiotherapy
. In particular, the intensity of the radiation beam is varied across the area
of the beam, this allows the high dose region of the radiation beam to conform
very closely to the shape of the tumor. Many of the facilities within our
practice have intensity modulated radiotherapy available.
What is "Stereotactic Radiosurgery"?
Stereotactic Radiosurgery is usually used to treat tumors of the brain using a
single, precisely targeted, high dose of radiation. Since this type of
treatment requires absolute immobilization of the patient's head, an external
headframe is often temporarily secured to the patients head.
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