Radiation therapy : Cancer

Radiation therapy : Cancer 150 150 Tony Guo

Radiation therapy

  • One of the oldest nonsurgical methods of cancer treatment
  • 50% of all cancer patients will receive radiation therapy at some point in their treatment
  • Radiation is emission of energy from a source and travels through space or some material
  • Different types of ionizing radiation are used to treat cancer
  • Technologic advances
    • Low-energy beams
      • Expend energy quickly
      • Penetrate a short distance
      • Useful for skin lesions
    • High-energy beams
      • Greater depth of penetration
      • Suitable for optimal dosing of internal targets while sparing skin
  • Total doses divided into fractions
  • Typically delivered once a day for 5 days a week for 2 to 8 weeks
    • Standard fractionation
    • Certain tumors are more susceptible to the effects of radiation than others
    • Simulation
      • A process by which radiation treatment fields are defined, filmed, and marked out on skin
      • Radiation oncologist specifies dose and volume of area to be treated
    • Immobilization device
      • The patient is positioned on a simulator, which is a diagnostic x-ray machine that recreates the actions of the linear accelerator and the radiation fields are marked on the patient’s skin.
      • Simulation uses immobilization devices to help the patient maintain a stable position.
      • In this example, a head holder and immobilization mask may be used to ensure accurate positioning for daily treatment of head and neck cancer.
    • Linear accelerator
      • A linear accelerator, which generates ionizing radiation from electricity and can have multiple energies, is the most commonly used machine for delivering external beam radiation.
    • Internal radiation
      • Patient is emitting radioactivity
      • Limit amount of time near patients being treated
        • Organize care
        • Use shielding
        • Wear film badge to monitor exposure

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