Radiation for a Brain Tumor
The goal of radiation therapy is to slow or help control tumor growth. It uses painless X-rays to destroy tumor cells. Radiation therapy can be used alone or with other types of treatment such as surgery or chemotherapy. If your doctor has selected radiation therapy for you, you may receive one of several types of external beam radiation, or internal radiation, called brachytherapy.
External beam radiation
There are five main main types of external beam radiation therapy.
3 dimensional conformal radiation therapy (3DCRT) uses multiple different directions for the radiation to minimize damage to nearby tissues.
Intensity modulated radiation therapy (IMRT) uses a computer driven machine that moves around the person's head as it delivers radiations.
Proton beam radiation therapy uses proton beams instead of X-rays. The proton beams release their energy at a specific distance of travel and thereby minimize damage to surrounding tissues. Other heavy ion beams are also under study for use.
Whole brain radiation is used to treat multiple tumors or cancer that has spread through the brain. It involves radiation to the entire brain and may have more severe side effects.
Stereotactic radiosurgery involves a single high dose of radiation, or occassionally several high doses. Since it is very focused, the normal tissue around the tumor receives little or no radiation. A machine will beam the radiation to the tumor. Two of the most common machines used are the gamma knife (which produces gamma rays) and the linear accelorator (which produces X-rays).
Brachythera py (internal radiation)
Small radioactive seeds are placed in or near the tumor during surgery or through tubes called catheters. The radiation only travels a short distance internally so damage to surrounding tissue is reduced. Stronger radioactive seeds are used more commonly and may be removed after minutes or up to 7 days. Weaker seeds may remain in place permanently and become inactive.
Side effects will vary with the type and strength of radiation used, the tumor type and the location, among other variables.
Short-term side effects and risks are brain swelling, fatigue, nausea, vomiting, infection, bleeding, dizziness, headache, seizures, hair loss, hearing loss, and skin changes in the treated area.
Long-term side effects and risks are memory loss, trouble thinking, permanent hair loss, hormonal changes, and necrosis (death of surrounding tissue).