Library/Glossary

  • Accelerated Therapy
    Radiation treatment in which the total dose is given over a shorter period of time.
  • Adjuvant Therapy
    A treatment used in addition to the main therapy.
  • Anesthesia
    A drug administered for medical or surgical purposes that induces partial or total loss of sensation and may be topical, local, regional, or general, depending on the method of administration and area of the body affected.
  • Anesthesiologist
    Medical doctor who specializes in administering anesthesia.
  • Aperture
    ApertureA custom-made, brass ring through which the beam can be shaped. The aperture is shaped to match the target, and it blocks the undesired radiation. It is contoured to exact shape of the target volume. Used with an compensator (see definition).
  • Arch System/Bite Block
    Arch System/Bite BlockA device that has a dental bite attachment that is used for immobilizing a patient's head and neck during treatment.
  • Benign Tumor
    A non-cancerous tumor.
  • BID Treatment
    Treatment that occurs twice daily. BID is an abbreviation for "bis in die," which means twice a day in Latin.
  • Biopsy
    The removal of a tissue sample that is examined for the presence of cancerous cells.
  • Brachytherapy
    Radiation therapy in which a sealed source of radiation is placed in or close to the tumor.
  • Bragg Peak
    Bragg PeakA pronounced region of increased energy deposition that occurs when a beam of charged particles, such as protons, slows to a stop in matter.
  • Cancer
    A term used to describe many different diseases, all of which involve the uncontrolled, abnormal growth of cells.
  • Cathetar
    A flexible or rigid tube used to drain fluids from body cavities or to distend body passages, especially one for passing into the bladder through the urethra to draw off urine or into the heart through a leg or arm vein for diagnostic examination.
  • Chemotherapy
    The treatment of cancer using specific chemical drugs that are selectively destructive to malignant cells and tissues.
  • Compensator
    CompensatorA custom-made, Lucite cylinder through which a proton beam is delivered. It is used to absorb some energy from the proton beam so that it stops just over the distal edge of the target. In this way, normal tissues beyond the target are not irradiated. Used with an aperture (see definition).
  • Computed Tomography Scan (CT or CAT Scan)
    A series of X-ray images, taken while rotating the X-ray source around the subject, that are processed by computer to provide a 3D view of the body.
  • Cone Down
    Term used to describe the procedure of reducing the size of treatment area. Typically, we treat a larger treatment volume at the beginning of treatment. After achieving a certain dose, the fields are reduced in size (“cone down”) for the remainder of the treatment. There may be more than one cone down during the course of treatment.
  • Conformal Radiation Therapy
    Treating diseased tissue with shaped radiation fields that avoid adjacent and normal tissue.
  • Consultation
    Initial evaluation by a physician. Our consultations involve a physical exam, review of medical records, and a discussion of the best and available options for treatment of the patient’s condition. We also will determine if the patient is a candidate for proton therapy.
  • Critical Structures
    Healthy tissues or organs near the tumor that must be protected from high doses of radiation.
  • Cyclotron
    A cyclotron is a machine used to accelerate charged particles to high energies and is used to generate the proton beam used for treatment. The cyclotron at IUCF/MPRI accelerates protons to an energy equivalent of just over 200 million volts (a speed of 380 million miles per hour).
  • Dosimetrist
    Radiation therapy practitioner responsible for production of the patient's treatment plan along with the physician and any associated quality assurance components.
  • Endorectal Coil MRI
    An MRI scan augmented with a rectal probe to improve the visualization of prostate cancer.
  • Entrance Dose
    A dose of radiation deposited near the surface of the body before the beam reaches the tumor.
  • Exit Dose
    A dose of radiation deposited in healthy tissue beyond the tumor site. Proton therapy does not have an exit dose. (see Bragg Peak)
  • Fiducial Marker
    Fiducial MarkerAn implanted marker of different materials (coil, seed, BBs) used in treatment planning and is used as a fixed standard of reference for comparison or measurement. Fiducials are implanted surgically in bone or soft tissue and are visible on X-rays images.
  • Fractionation
    Spreading out the dose over time. In the USA, Australia, and Europe, the typical fractionation schedule for adults is 180 to 200 cGy per day, five days a week.
  • Gamma Knife
    A gamma knife is a device used to treat brain tumors with a single high dose of radiation.
  • Gantry
    GantryA rigid frame that supports, and rotates, the dose delivery equipment about the patient.
  • Gleason Score
    The Gleason staging system is used to evaluate the prognosis of men with prostate cancer and to help guide therapy. The Gleason score is based on the microscopic appearance of biopsied prostate tissue.
  • Gray
    A measure of absorbed radiation dose (absorbed energy). One Gray equals 100 centiGray(cGy).
  • Immobilization Device
    Immobilization DeviceA custom-made device, such as a mold or mask, that holds the patient stationary during treatment to ensure the precise localization of therapeutic radiation.
  • Magnetic Resonance Imaging (MRI)
    A diagnostic imaging procedure (no radiation involved) useful for locating soft tissue injuries or abnormalities.
  • Malignant
    Progressive and uncontrolled growth, especially of a tumor.
  • Medical Oncologist
    A physician who uses chemotherapy to treat cancer.
  • Medical Physicist
    Performs or supervises the procedures necessary to ensure the safe and effective delivery of radiation in patient care.
  • Medical Physics Team
    A branch of applied physics concerning the application of physics to medicine. It generally concerns physics as applied to medical imaging and radiotherapy, although a medical physicist may also work in many other areas of health care.
  • Metastasis
    Spreading of cancerous cells from an original site to other places in the body.
  • Mixed Modality
    A modality is a type of radiation treatment: X-rays, protons, etc. A treatment that consists of one modality followed by another is called a mixed modality.
  • Nozzle
    The portion of the proton beam delivery system closest to the patient. The nozzle contains devices for monitoring the dose and shaping the dose to the target.
  • Oncologist
    A doctor who specializes in treating cancer.
  • Photon
    A single particle of light. X-rays and ultraviolet light are energetic photons. Visible light and microwaves are less energetic. X-rays and higher energy photons can penetrate tissue and irradiate deep targets.
  • Positron Emission Tomography (PET Scan)
    A nuclear medicine imaging procedure that can identify areas of cancerous tissue based on their higher than normal metabolic activity.
  • Prostate-Specific Antigen (PSA)
    A protein in the blood that can be measured to detect or monitor prostate cancer.
  • Protocol
    A course of treatment designed to eradicate cancer.
  • Proton
    A positively charged subatomic particle. Protons are not radioactive. Fast moving protons can penetrate tissue and deposit energy in deep targets.
  • Proton Therapy
    Proton therapy uses a beam of protons to irradiate diseased tissue, most often in the treatment of cancer. It is a precise form of radiation treatment that minimizes damage to healthy tissue and surrounding organs.
  • Radiation
    Radiation is energy carried by particles or waves through space. Sunlight is a form of radiation, so are radio waves and microwaves. X-rays and gamma-rays are energetic forms of light that can penetrate the human body.
  • Radiation Oncologist
    A doctor who specializes in the use of radiation to treat cancerous or non-cancerous tumors. A radiation oncologist reviews the medical findings with the patient and discusses treatment options and the benefits of radiation as well as the possible side effects.
  • Radiation Therapist (RTT)
    A specially trained medical technologist that is responsible for delivering the patient’s daily treatment.
  • Radiation Therapy
    Radiation therapy uses high-energy, penetrating waves, or particles, to treat cancer cells.
  • Radiotherapy
    Another term for radiation therapy (see above).
  • Registered Nurse (RN)
    A graduate nurse who has passed a state board examination and has been registered and licensed to practice nursing.
  • Robot Positioner
    A robot that is adapted for the precise positioning of patients during radiotherapy treatments.
  • Side Effects
    A peripheral or secondary effect.
  • Simulation
    The use of X-ray images to plan a course of radiation treatment.
  • Snout
    The portion of the nozzle closest to the patient. The snout supports the aperture and compensator, and shields the patient from extraneous radiation.
  • Stationary Beam Line
    Also called a fixed-beam line. A stationary beam line does not move around the patient (as opposed to a rotating-beam line in the gantry rooms).
  • Synchrotron
    A synchrotron is a machine used to accelerate charged particles to high energies. Synchrotrons reach energies thousands of times higher than do cyclotrons.
  • Targeting Markers (Fiducials/Seed Implant)
    Markers placed internally or at the skin surface to document location.
  • TomoTherapy
    A type of X-ray radiation therapy that is highly conformal, and combines a therapy unit with the rotating structure of a CT scanner.
  • Treatment Field
    The area in the body to be treated by the radiation beam.
  • Treatment Planning
    The process by which beam delivery is optimized for a given patient and clinical situation.
  • Tumor
    An abnormal growth of tissue resulting from the uncontrolled, progressive multiplication of cells.
  • Verification Simulation (V-Sim)
    A dry run of the treatment process to verify the correct positioning of the patient and the targeting of the radiation field prior to beam delivery.