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Glossary of Terms AVM (Arteriovenous Malformation) AVM is an abnormal combination of entangled blood vessels in the brain that are prone to bleed. This bleeding can cause symptoms ranging from headaches and seizures to neurological catastrophes and even death. Benign tumor Benign tumors are not cancerous; however, they may need to be treated. Some benign tumors may change over time and become malignant. Bite block A bite block is a mouth guard that affixes to the patient’s upper lip. It has sophisticated markings (fiducials) that are tracked by an optical camera. The fiducials allow the patient to be precisely positioned on a repeated basis. A bite block is generally used during a stereotactic radiotherapy (SRT) treatment. Chemotherapy Chemotherapy is a treatment that destroys tumor cells through the use of chemicals that are injected into the body or taken orally over a period of time. "Conformal" radiosurgery Conformal radiosurgery shapes the radiation beam to fit the tumor or malformation perfectly, rather than using the traditional method of multiple circular beams. Conformal radiosurgery maximizes radiation to the tumor or malformation and minimizes doses to surrounding healthy tissue. CNS (Central Nervous System) The brain and spinal cord together form the CNS. CT (Computerized Tomography) A CT scan is a diagnostic imaging technique where an x-ray machine and computer are used to create a detailed picture of the body’s tissues and structures. A dye, or contrast agent, may be injected into the patient to highlight abnormalities in tissue. Critical structures Critical structures are areas in the brain that are responsible for such vital functions as memory, speech, hearing, sight and movement. The spinal cord is the critical structure in the spine. CyberKnife Synchrony CyberKnife Synchrony is a technology developed in order to deliver dynamic radiosurgery to tumors that move with respiration. The Synchrony system precisely tracks tumors in or near the lungs as they move, enabling highly focused beams of radiation to destroy the tumors with minimal damage to adjacent normal tissue. Fiducials Fiducials are markings found on either the head frame or bite block. Additionally, they may be surgically implanted to treat spine or other tumors. The fiducials act as markers, helping to identify precisely the location of the tumor. Fractionation Fractionation, or staging, occurs when the total dose of radiation is divided into smaller doses in order to give healthy tissue time to repair itself. Gamma Knife The Gamma Knife uses older radiation technology that is confined to treating tumors in the head. The Gamma Knife uses ionizing radiation (gamma rays) produced by 201 cobalt-60 sources to target the tumor or abnormality. Glioma Gliomas, or tumors that arise from the supportive tissue of the brain, are the most common primary brain tumors. Astrocytomas, ependymomas, oligodendrogliomas and tumors with mixtures of two or more of these cell types are the most common gliomas. Head frame The head frame is a metal halo that is fixed to the patient’s skull. It contains markings (fiducials), which are visualized on the CT and/or MRI image. Local anesthesia is used to secure the head frame into position with four micro-pins. Technologies such as the Gamma Knife use a head frame because they do not have image guidance capabilities. Image guidance system An image guidance system is utilized by the CyberKnife Radiosurgery system that tracks and verifies tumor location to enable automatic compensation for patient movement during the procedure. The image guidance system’s sophisticated technology allows for 100% frameless treatments with the ability to achieve submillimeter accuracy without the use of a painful head frame. IMRT (Intensity Modulated Radiation Therapy) IMRT is a form of three-dimensional conformal radiation therapy (3D-CRT) that links treatment planning and driver software to the actual treatment delivery devices. As a result, clinicians can determine and deliver an optimum plan of individualized radiation for each patient. Inaccessible tumor An inaccessible tumor cannot be removed surgically because it is located in an area that is difficult to access surgically without risk to the nervous system or vital areas of the brain. Isocentric Treatment Planning Isocentric treatment, or multi-isocentric treatment, involves packing the lesion with a single (or multiple, overlapping) spherically shaped dose distributions. Hot spots During certain types of radiation treatment, hot spots are areas where radiation beams overlap, causing overdosing in some areas. Overdosing may increase the risk of complications as a result of excessive radiation exposure to normal tissue, including critical structures such as the highly radiosensitive optic chiasm and acoustic nerves. Cold spots During certain types of radiation treatment, cold spots are areas on the target that receive underdosing. Consequently, tumor cells may not be fully destroyed. Linac Linac, or linear accelerator, delivers x-ray radiation treatment by moving in an arc around the patient’s head while delivering narrow beams of collimated radiation. The ability to reach some tumors may be difficult due to the restrictions of the arc, making it more challenging to treat some tumors. Lumbar puncture A lumbar puncture, or spinal tap, is a procedure used to withdraw a small sample of cerebrospinal fluid so that it can be examined for abnormal cells. Malignant A malignant tumor is cancerous and behaves in an aggressive manner. Meningiomas Meningiomas are thin membranes that cover the brain and develop from the meninges. They appear most often in middle-aged adults and children. Metastatic tumor A metastatic tumor is caused by cancer cells that originate elsewhere in the body and travel to the current site through the bloodstream. MRI (Magnetic Resonance Imaging) MRI uses a magnetic field rather than x-rays to produce a better picture of a tumor that is located near a bone. An MRI does not use radiation. PET (Positron Emission Tomography) PET is an imaging technique that provides a picture of brain activity by measuring levels of injected glucose sugar labeled with a radioactive marker. Primary Brain Tumor A primary brain tumor arises from cells in the brain or surrounding tissue. Multi-jointed robotic arm Utilized by the CyberKnife Radiosurgery system, the multi-jointed robotic arm enables access to previously unreachable tumors and reduces damage to surrounding critical structures. Non-isocentric treatment Non-isocentric treatment is a system of radiation in which beams originate from arbitrary points in the workspace and are delivered to the lesion. The result is an even concentration of radiation within the lesion. Non-isocentric radiation is offered exclusively with CyberKnife Radiosurgery. Six Degrees of Freedom The CyberKnife system’s computer-controlled robotic arm has six degrees of freedom. The robot can position the linac to more than 100 specific locations, or nodes. Each node has 12 possible approach angles, translating to over 1,200 possible beam positions—the greatest flexibility of approach available in any stereotactic radiosurgery system. Stereotactic Stereotactic imaging is the ability for a physician to identify the 3D location of a tumor with a high degree of accuracy. Stereotactic radiotherapy (SRT) Stereotactic radiotherapy delivers lower doses of focused radiation over a series of treatment sessions, giving a larger overall dose of radiation to the tumor. Each treatment is called a fraction, therefore, this type of therapy is sometimes called a “fractionated” therapy. A bite block that fixes to the patient’s upper teeth or mask may be used in place of a head frame for head treatments. Stereotactic radiosurgery (SRS) Stereotactic radiosurgery delivers a high dose of radiation, generally in one treatment. For brain surgery, SRS generally requires the use of a stereotactic frame that is fixed onto the patient’s skull. The CyberKnife system allows physicians to perform SRS procedures without the use of a stereotactic frame, which can be less traumatic and less painful for the patient. T4 accuracy Tight-to-the-Tumor accuracy is available only with the CyberKnife system and allows for the treatment of complexly shaped tumors. T4 accuracy is made possible with the CyberKnife system’s unique combination of a proprietary image guidance system and a multi-jointed robotic arm. Treatment planning The CyberKnife system provides a wide range of treatment options, including the ability to use either forward or inverse treatment planning, allowing the physician to customize each patient’s treatment plan. Forward treatment planning The physician determines what dose to deliver from a particular targeting position. The planning software calculates the total dose within the lesion. Inverse treatment planning The physician specifies the total dose to be delivered to the tumor and sets boundaries to protect critical structures. The software determines targeting positions and the dose to be delivered from a particular targeting position. |
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CyberKnife is the only FDA approved completely Robotic 
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Home | What is Radiosurgery | What is CyberKnife® | Treatment Types | The Team | Contact Us | Directions To learn more about the revolutionary cancer treatment call the CyberKnife Center of New York coordinator at 607.763.6666 or visit these Web sites:
CyberKnife® technology was developed by Accuray in conjunction with Stanford University |