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Radiation therapy is a treatment that uses high energy x-rays to kill or shrink cancer cells, to manage pain (palliative care) or to prevent cancer from spreading to the brain. There are several kinds of radiation:

  • External Beam Radiation delivers beams of radiation from outside of the body aimed at tumors with the goal of killing the tumor. The linear accelerator (Linac) is the most commonly used machine to deliver external beam radiation.
    • 3D  CRT (Conformal Radiation Therapy): Uses imaging tools like CT or PET scans to create a computer model of the tumor. Radiation is then delivered directly to the area within this tailored field. In this method, radiation intensity is the same throughout the radiation beam.
    • Intensity Modulated Radiation Therapy (IMRT): The intensity of the radiation can be changed throughout treatment. The linear accelerator (LINAC) is the most commonly used machine to deliver external beam radiation. Tomotherapy is a type of IMRT.
  • Stereotactic Radiation delivers highly concentrated, targeted beams of radiation into the tumor. There are two types of stereotactic radiation, Stereotactic Radiosurgery, or SRS, which is to the brain and Stereotactic Body Radiation Therapy (SBRT), which is to other parts of the body. Stereotactic radiation is usually given in one to five sessions with high doses of radiation. 
    • Linear accelerator based (LINAC)—the most well-known machines are Novalis Tx® and CyberKnife®, used for treating tumors in the lung, brain, and bone
    • Cobalt 60 based (photon)—the most well known machine is Gamma Knife®, which is designed exclusively for treating brain tumors
    • Particle beam (proton)—only exists in a handful of centers in the US and is used to treat tumors in the lung, brain, and bone
  • Whole brain radiation:  External beam radiation therapy to the head. In lung cancer this type of radiation is used to treat brain metastases.
  • Prophylactic Cranial Irradiation (PCI): Radiation to the head with the goal of reducing the risk of or preventing brain metastases from occurring. It is commonly recommended after successful treatment for SCLC.
  • Brachytherapy (internal or implant radiation therapy): Radioactive material sealed in needles, seeds, wires or catheters is placed directly into or near a tumor.