Radiation Therapy for Brain Tumors
Modern neurosurgical tools and techniques and advanced imaging modalities such as CT and MRI now allow brain tumors to be identified much earlier in the course of the disease. Even when a cure is not possible, an earlier diagnosis can result in an improved outcome for the patient through more appropriate utilization of radiation therapy.
Radiation therapy uses high energy light beams (X-rays or gamma rays) or charged particles (electron beams or proton beams) to damage critical biological molecules in tumor cells. If enough damage is done to the chromosomes of a cell, it will spontaneously die or it will die the next time it tries to divide into two cells. Radiation therapy is usually done on an outpatient basis with treatment occurring each workday for a period of several weeks. If the patient has had surgery for the tumor, radiation therapy typically begins a week or two after surgery.
Radiation therapy is an effective cancer therapy. In surgery, a surgeon may be constrained in resecting the cancer by the presence of critical structures that cannot be removed. The side effects of chemotherapy on normal tissues far away from the brain may limit the ability of a medical oncologist to deliver appropriately intensive treatment to a brain tumor. In radiation therapy, a non-invasive treatment can be given repetitively over several weeks to months and can be aimed specifically at the area where treatment is needed, minimizing side effects for uninvolved normal tissues.
This repetitive treatment is called fractionation because a small fraction of the total dose is given in each treatment. The skills of the radiation oncologist, physicist and dosimetrist allow complex plans to be devised to minimize side effects for normal tissues. Radiotherapy can only be performed with linear accelerator technology.
Conventionally administered external beam radiation therapy gives a uniform dose of radiation to the entire region affected by the tumor. There is only a small variation of the dose delivered to various parts of the tumor. Radiation therapy may not be as effective as stereotactic radiosurgery, which can give higher doses of radiation to the tumor itself.
SBRT – Stereotactic body radiation therapy – is a specially designed coordinate-system that is used for the exact localization of the tumors in the body in order to treat it with limited but highly precise treatment fields. SBRT involves the delivery of a single high dose radiation treatment or a few fractionated radiation treatments (usually up to 5 treatments). A high potent biological dose of radiation is delivered to the tumor, improving the cure rates for the tumor, in a manner previously not achievable by standard conventional radiation therapy.
Treatment of brain tumors with external beam radiation therapy has been an area of intense research activity over the past several decades. Through clinical research, conducted on patients, much has been learned about how to appropriately use radiation therapy for various types of brain tumors. External beam radiation therapy is a valuable component of therapy for nearly all brain tumors; treatment can be delivered to any part, or all, of the central nervous system. The ability to assure uniform doses of radiation to the areas being treated is one of the major strengths of modern external beam radiation therapy.
To find a radiation oncologist in Memphis, Tennessee, please use our physician locator or call 888.777.5959.