Brain tumor Radiation therapy

In case of a malignant brain tumor, radiation therapy is needed to control the tumor and possibly acheive long-term remission. There are some possible side effects of radiation therapy; these include the possibility of strokes and Dementia. The severity as well as the chance that they happen, worsen with higher doses of therapy. The radiation therapy is usually very well tolerated.

Stereotactic Radiosurgery:

Stereotactic radiosurgery is a special form of radiation therapy - it is not surgery. Stereotactic radiosurgery allows precisely focused, high dose X-ray beams to be delivered to a small, localized area of the brain. It is used to treat small brain and spinal cord tumors (both benign and malignant); blood vessel abnormalities in the brain; deﬁned areas of cancer; certain small tumors in the lungs and liver; and neurologic problems such as movement disorders.Stereotactic radiosurgery is given in a single session. If given in multiple sessions, the treatment may be called stereotactic radiotherapy or fractionated stereotactic radiotherapy. “Frameless radiosurgery” refers to radiosurgery that does not use a metal frame to immobilize the head during treatment. Rather, markers able to be viewed on a scan are placed on the scalp, or a face mask is used to help hold the head steady. The treatment equipment is then aligned with the markers or with the face mask.

Radiosurgery is different from Conventional Radiation therapy. Conventional external beam radiation therapy – the most common form of radiation therapy – delivers full dose radiation to the tumor and some of the surrounding brain tissue. For several reasons, the target area for conventional radiation deliberately includes a border (called a “margin”) of normal brain around the tumor. These reasons include uneven tumor borders, the risk of invisible spread of the tumor into the surrounding tissue, a larger tumor size, or the presence of multiple tumors. This larger zone of full-dose radiation includes the borders of the tumor where microscopic tumor cells may be located. Since normal brain tissue is included in the full-dose region, conventional radiation is broken down into small daily doses so the normal brain tissue can tolerate it. As a result, reaching the desired dose of radiation takes several weeks of daily treatment. Radiosurgery focuses radiation beams more closely to the tumor than conventional external beam radiation. This is possible through the use of highly sophisticated computer-assisted equipment. A head frame or facemask used for this treatment allows very precise set up, localization and treatment of the tumor. Using advanced computer planning, radiosurgery minimizes the amount of radiation received by normal brain tissue and focuses radiation in the area to be treated. Since conventional radiation therapy covers more normal tissue, it can often be given only once. Radiosurgery, however, may be considered for re-irradiation due to its precision and the possibility of avoiding previously treated areas

Gamma knife, Linear Accelerators, Proton Beam radiosurgery units are the types of equipment used in Radiosurgery. Radiosurgery requires a team of specialists. That team may include a neurosurgeon, radiation oncologist, radiologist, radiation physicist, neurologist, anesthesiologist, specially trained nurses, technologists and the unit support staff.The actual treatment time for any of these techniques generally ranges from 15 minutes to about two hours.

Some people have few or no side effects from this type of radiation therapy. Once they have rested following the treatment and have resumed their regular activities, tenderness at the pin sites may be the only side effect Early symptoms are often due to brain edema (swelling) caused by the radiation. These symptoms can include nausea, vomiting, dizziness, or headaches which are usually temporary. Once the swelling resolves, these symptoms usually resolve. Two to three weeks after treatment, some may experience hair loss in the area radiated, but this does not occur in everyone. Hair loss depends on the dose of radiation received by portions of the scalp and the ability of the radiated hair follicles to heal. Regrowth usually begins in 3-4 months, and may be a slightly different color or texture than before. The scalp may also become temporarily irritated. Some patients may experience delayed reactions weeks or months after treatment. These reactions can include necrosis or cell death in the high radiation dose region due to swelling in reaction to the radiation effect on the target region. These symptoms are mainly due to swelling or death of brain tissue in the treated area. They may mimic the symptoms of tumor regrowth or stroke. Treatment will be based on the type of side effect that occurred. Other effects depend on the location of the tumor.