Glossary of Terms

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  • a

  • To remove or destroy. An ablative dose of radiation is designed to destroy the cancer cells while minimizing risk of radiation dose to surrounding healthy tissue.
  • (or vestibular schwannoma) Benign tumor that develops on the balance (vestibular) and hearing, or auditory (cochlear) nerves leading from your inner ear to the brain. Pressure from the tumor can lead to imbalance, hearing loss and ringing in the ears.  
  • Diagnostic test using x-ray or computer imaging to view the blood vessels and blood flow.
  • (AVM) Tangle of abnormal blood vessels in the brain, weakening and possibly rupturing affected arteries and veins.  
  • Graph or chart that shows the softest sounds a person can hear at different pitches or frequencies, it measures the degree of hearing loss.
  • b

  • A tumor that is not cancerous or malignant. It does not spread to other parts of the body, but can be equally as dangerous as a cancerous or malignant tumor if it is compressing vital structures, such as blood vessels, nerves, or over producing certain hormones.
  • Bilateral Microphones with Contralateral Routing of Signal – Hearing aid recommended for people with hearing loss in both ears, but one ear hears substantially “better” than the other.
  • (also called internal radiation) Is a form of radiotherapy where a sealed radiation source is placed inside or next to the area requiring treatment. 
  • c

  • Clear, colorless body liquid surrounding the brain and spinal cord; serving as a barrier against shock.
  • Cancer treatment that is administered through the use of drugs that are injected into the body, taken orally over a period of time, administered by infusion or through the skin. This is a form of systemic therapy – i.e., as the drugs circulate in the bloodstream, the entire body is affected.
  • Central Nervous System — The brain and spinal cord. It gathers information from all over the body and coordinates activity.
  • Refers to normal tissues near the tumor. Damage to critical structures can often lead to problems for patients and side effects. For example, the spinal cord is the primary critical structure of concern when treating spinal lesions.
  • Computed Tomography — A diagnostic imaging technique that uses computerized X-ray imaging procedure to create detailed 3D images of tissues and structures in the body. A dye, or contrast agent, may be injected into the patient to highlight structures and abnormalities.
  • e

  • The use of radiation delivered from outside the body to kill cancer cells or shrink tumors.
  • Refers to any location of the body “outside of the brain”. Examples of extracranial sites include the spine, lung, pancreas, and other areas of the body.
  • f

  • Fiducials are markers that are placed around a tumor for the purpose of better identifying and tracking a tumor on an X-ray.
  • g

  • A grading system to determine the cancer’s aggressiveness.  The Gleason score usually ranges from 6 to 10. The lower the Gleason score, the more the cancer cells look like normal cells. The Gleason score is used to help identify treatment options and determine the patient’s prognosis (outcome).
  • Tumor in the brain or spinal cord that starts in the glial cells.
  • h

  • The buildup of fluid in cavities in the brain, which puts pressure on the brain and leads to a wide range of symptoms, including headaches, nausea, imbalance, incontinence and more.
  • Dividing the total dose of radiation into multiple smaller doses (usually administered daily), thereby permitting the surrounding exposed healthy tissue time to repair.
  • i

  • (also called biologic therapy): Type of cancer treatment that helps your immune system fight cancer and other diseases. Immunotherapy treatments use substances made by the body or in a laboratory to improve or restore immune system functionality.
  • Refers to “inside the skull” or brain.
  • The use of radiation to kill cancer cells or shrink tumors.
  • l

  • (LINAC) Commonly used device that delivers external beam radiation treatments for patients with cancer. It delivers high-energy x-rays or electrons to the region of a patient’s tumor. 
  • m

  • A cancerous tumor. Abnormal collections of cells that can invade and destroy nearby and distant tissues and organs.
  • A member of the radiation oncology team who has knowledge of the overall characteristics and clinical relevance of radiation oncology treatment machines and equipment. Ensures the radiation treatment delivers the most lethal dose to the tumor with the fewest side effects to healthy organs.
  • Professional with education and specialist training in the concepts and techniques of applying physics in medicine.
  • A serious form of skin cancer that begins in the cells that control the pigment of your skin.
  • Tumors that originate in the membranes surrounding the brain and spinal cord.
  • The spread of cancer cells to new areas of the body. A metastatic tumor has spread from the place where it first formed to another part of the body. 
  • The spread of cancer cells to new areas of the body. A metastatic tumor has spread from the place where it first formed to another part of the body. 
  • Magnetic Resonance Imaging — An imaging technique that uses magnetic fields rather than X-rays to create 3D images of structures in the body. An MRI generally provides more detailed images of soft tissue anatomy (as opposed to bone) compared to a CT scan. A dye may be injected prior to the scan to improve visualization of many tumors. MRI scans are painless.
  • Combining multiple methods to treat cancer. For example, using radiotherapy and surgery.
  • n

  • Death of cells in body tissue or organs because of injury, disease or failure of the person’s blood supply. 
  • Treatment administered as a first step to shrink a tumor before the main treatment, usually surgery, is given.
  • Physician who specializes in the diagnosis and treatment of central and peripheral nervous system disorders
  • o

  • (also called postural hypotension) Type of low blood pressure that happens when standing up after sitting or lying down, leading to feelings of dizziness, lightheadedness and faintness.  
  • p

  • Positron Emission Tomography – An imaging technique that provides a picture of cellular activity by measuring positrons emitted from injected substances "labeled" with a radioactive marker. PET scans help determine if a lesion has increased activity that may be a sign of rapid cell growth indicating a tumor.
  • Benign, slow-growing tumors or growths on the pituitary gland.
  • Prostate Specific Antigen – Protein produced by the prostate gland found in the blood. Higher levels of PSA in the blood may indicate there is a problem with the prostate (e.g., prostate cancer, an infection, inflammation of the prostate gland). 
  • The PSA test measures the level of PSA in the blood.
  • r

  • Physician who has special training in using radiation to treat cancer.
  • Administers radiation treatments for cancer patients.
  • An operation to remove the prostate gland and tissues surrounding it. 
  • Medical doctor specializing in medical imaging to support diagnosis and treatment of various diseases. 
  • (also called radiation therapy) Cancer treatment that uses radiation to kill cancer cells or reduce tumor size. 
  • s

  • Stereotactic Ablative Radiotherapy — Another term for SBRT (Stereotactic Body Radiation Therapy).
  • Stereotactic Body Radiation Therapy — A radiation therapy approach which delivers high dose radiation to a target within the body, in either a single treatment session or up to no more than five treatment sessions. Each session is typically referred to as a “fraction.”
  • Form of radiation therapy for prostate cancer. The terms "brachytherapy" or "internal radiation therapy" might also be used to describe the procedure.
  • Stereotactic Radiosurgery — A non-surgical radiation therapy approach used to treat functional abnormalities and small tumors in the brain. High-dose, precisely-targeted radiation is delivered in fewer treatment sessions than conventional radiotherapy, typically just 1 to 5 sessions, which can help preserve healthy tissue.
  • “Stereo” makes reference to one’s position within 3-dimensional space. Stereotaxy or stereotaxis is the science and practice of precisely locating a tumor within 3D space. Also known as Stereotaxis or Stereotaxy.
  • t

  • The degree a substance can cause harm to humans.
  • In radiotherapy, it is the process in which a team consisting of radiation oncologists, radiation therapists, medical physicists and medical dosimetrists plan the appropriate radiotherapy treatment for a patient with cancerous or non-cancerous tumors.
  • Chronic pain condition that affects the trigeminal nerve, which carries sensation from the face to the brain. Patients can experience excruciating pain in the areas of the face where the branches of the nerve are distributed including the upper and lower jaws, scalp, forehead, eyes, nose and lips.
  • u

  • Physician who specializes in diseases of the urinary organs in females and the urinary and sex organs in males.
  • v

  • General term for vascular anomalies of veins, lymph vessels and/or arteries. Often congenital (present at birth) and can cause functional or cosmetic problems.

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Important Safety Statement: Most side effects of radiotherapy, including radiotherapy delivered with Accuray systems, are mild and temporary, often involving fatigue, nausea, and skin irritation. Side effects can be severe, however, leading to pain, alterations in normal body functions (for example, urinary or salivary function), deterioration of quality of life, permanent injury and even death. Side effects can occur during or shortly after radiation treatment or in the months and years following radiation. The nature and severity of side effects depend on many factors, including the size and location of the treated tumor, the treatment technique (for example, the radiation dose), the patient’s general medical condition, to name a few. For more details about the side effects of your radiation therapy, and if treatment with an Accuray product is right for you, ask your doctor.