Glossary of Terms

AJAX progress indicator
  • b
  • Benign Tumor
    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.
  • c
  • Chemotherapy
    Cancer treatment that is administered through the use of drugs that are injected into the body or taken orally over a period of time. This is a form of systemic therapy – i.e., as the drugs circulate in the bloodstream, the entire body is affected.
  • CNS
    Central Nervous System — referring to the collection of nerves and structures that make up the brain and spinal cord.
  • Critical Structures
    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.
  • CT
    Computerized Tomography — A diagnostic imaging technique that uses an X-ray machine and computer 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
  • Extracranial
    Refers to any location of the body “outside of the skull”. Examples of extracranial sites include the spine, lung, pancreas, and other areas of the body.
  • f
  • Fiducials
    Fiducials are markers that are placed into a tumor for the purpose of better identifying and tracking a tumor on an X-ray.
  • h
  • Hypofractionation
    Dividing the total dose of radiation into multiple smaller doses (usually administered daily), thereby permitting the surrounding exposed healthy tissue time to repair.
  • i
  • Intracranial
    Refers to “inside the skull” or brain.
  • m
  • Malignant Tumor
    Abnormal collections of cells that can invade and destroy nearby and distant tissues and organs.
  • MRI
    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.
  • n
  • Neoadjuvant Therapy
    Treatment administered as a first step to shrink a tumor before the main treatment, usually surgery, is given.
  • p
  • PET
    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.
  • s
  • SABR
    Stereotactic Ablative Radiotherapy — Another term for SBRT (Stereotactic Body Radiation Therapy).
  • SBRT
    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.”
  • SRS
    Stereotactic Radiosurgery — A minimally invasive form of surgical intervention which makes use of a three-dimensional coordinate system to locate small targets inside the body and to perform on them some action such as ablation, biopsy, lesion, injection, stimulation, implantation, radiosurgery (SRS), etc.
  • Stereotactic
    “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
  • Treatment Planning
    Customizing the radiosurgery treatment parameters (such as radiation dose and shape of the field) to the individual patient using specialized software.