Nuclear Oncology

Do you use this equipment

The Gamma Knife and the computer program associated treatment planning allows doctors to locate and irradiate relatively small areas of the head (primarily in the brain) with high accuracy. This will be administered radiation dose in the (s) area (s) to deal with little effect on the surrounding tissues. The gamma knife can be used for many types of problems, for example, to treat certain cancers that appear in the brain or come to this body (primary or metastatic brain tumors), benign brain tumors (meningiomas, pituitary adenomas , acoustic neuromas), defective blood vessels (AVMs) and functional problems (trigeminal neuralgia). They are studying future uses for epilepsy and Parkinson’s disease. The Gamma Knife is not generally useful in areas measuring more than three or four centimeters.

How does this team

The gamma knife uses a technique called stereotactic radiosurgery, which uses multiple radiation beams that converge in three dimensions to focus precisely on a small amount, like a tumor, this allows radiation doses to that volume safely. Current models of gamma knife uses advanced robotics to move the patient in submillimeter increments during treatment in order to focus the radiation successfully in all areas to be treated. Treatment with gamma knife are given in a single session.

Under local anesthesia, is coupled to the patient’s head with four screws, a rigid head frame that incorporates a special three-dimensional coordinate system. After imaging studies are obtained as MRI (MRI), computed tomography (CT) or angiography and the results are sent to the computer system planning gamma knife. Together, physicians (oncologists and neurosurgeons) and medical radiation physicists delineate areas to be treated and the normal anatomical structures and planning using the computer to determine the exact relationship between them and the head frame, and calculate the parameters for the Knife treatment gamma rays. The target areas are often treated better during the treatment session with a combination of several successive shots, commonly known as “shots.” Physicians and physicists routinely consider several fine adjustments of treatment parameters to determine the optimal dose and plan.

With three-dimensional coordinates determined in the planning process, the frame then fits very precisely the unity of the gamma knife to ensure that when the unit is activated, the area target is right in the middle of the 200 converging beams gamma radiation directed precisely (generated from cobalt 60). Treatment may take several minutes to several hours to complete, depending on the shape and size of the target, the number of “shots” and the required dose. The patient does not feel the radiation. The frame is removed from the head after stopping treatment and it is possible that the patient can resume normal activities.

For more information, see the stereotactic radiosurgery (www.RadiologyInfo.org/sp/info.cfm?PG=stereotactic).

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Who manages this team

Most patient safety is achieved by a multidisciplinary team approach. The team usually consists of a radiation oncologist, a medical radiation physicist and a neurosurgeon, who have received specialized training in the use of gamma knife, have the support of nurses, anesthesiologists (for patients who can not cooperate, as children) and radiation therapists, who work together to give patients high quality care they deserve. It is a requirement of the Nuclear Regulatory Commission that an “authorized user”, usually an oncologist, is in the treatment console during the entire procedure.