1:02 AM
kotesh
The goal of radiation therapy is to selectively kill tumor cells while leaving normal brain tissue unharmed. In standard external beam radiation therapy, multiple treatments of standard-dose "fractions" of radiation are applied to the brain. Each treatment induces damage to both healthy and normal tissue. By the time the next treatment is given, most of the normal cells have repaired the damage, but the tumor tissue has not. This process is repeated for a total of 10 to 30 treatments, depending on the type of tumor. This additional treatment provides some patients with improved outcomes and longer survival rates.
Radiosurgery is a treatment method that uses computerized calculations to focus radiation at the site of the tumor while minimizing the radiation dose to the surrounding brain. Radiosurgery may be an adjunct to other treatments, or it may represent the primary treatment technique for some tumors.
Radiotherapy may be used if there is incomplete resection of the tumor. Forms of radiotherapy used for brain cancer include external beam radiation therapy, brachytherapy ,and in more difficult cases, stereotacticradiosurgery, such as Gamma knife, Cyberknife or Novalis Tx radiosurgery, remains a viable option.[15]
Radiotherapy is the most common treatment for secondary cancer brain tumors. The amount of radiotherapy depends on the size of the area of the brain affected by cancer. Conventional external beam whole brain radiotherapy treatment (WBRT) or 'whole brain irradiation' may be suggested if there is a risk that other secondary tumors will develop in the future.[16] Stereotactic radiotherapy is usually recommended in cases of under three small secondary brain tumors.
In 2008 a study published by the University of Texas M. D. Anderson Cancer Center indicated that cancer patients who receive stereotactic radiosurgery (SRS) and whole brain radiation therapy (WBRT) for the treatment of metastatic brain tumors have more than twice the risk of developing learning and memory problems than those treated with SRS alone
