Radiation therapy uses high energy x-rays (photons) or particle beam (protons) to kill, shrink, control the growth of tumors, manage pain or to prevent cancer from spreading to other organs.

Radiation may be used alone or in addition to other treatments when the cancer cannot be removed by surgery or when surgery is not recommended due to other health conditions. Radiation also may be used before or after surgery.

Depending on the type of lung cancer, where it is located and other health conditions, different procedures may be recommended by your treatment team.

Radiation for lung cancer

External Beam Radiation

External Beam Radiation delivers beams of radiation from outside of the body through the skin with the goal of killing the tumor. Treatments are given daily over 6-7 weeks. There are several ways external beam radiation is used:

  • 3D-CRT (Conformal Radiation Therapy): Uses imaging tools like CT or PET scans to map the tumor before treatment. Photon radiation is then delivered directly to this area. In this method, radiation strength is the same throughout the radiation beam.
  • Intensity Modulated Radiation Therapy (IMRT): Similar to 3D-CRT but the strength of the radiation can be changed throughout treatment.
  • Image Guided Radiation Therapy (IGRT): Uses imaging such as CT, MRI or PET during the treatment process. This can result in more accuracy in photon radiation delivery and monitoring of treatment progress.
  • Particle beam (proton) Therapy is also a used to treat tumors in the lung. Fewer than 20 centers in the country offer proton therapy treatment.

Stereotactic Radiotherapy

Stereotactic Radiotherapy, also called Stereotactic Body Radiotherapy (SBRT) or Stereotactic Ablative Radiotherapy (SABR) is a very precise form of radiation used to target the tumor and spare nearby healthy tissue. The CyberKnife® System, the TomoTherapy® System, Varian TrueBeam™ and NovalisTX® are devices that can deliver stereotactic radiotherapy using these methods. Typically SBRT is given in one to five treatments. Proton therapy can also be used to perform SBRT. Fiducials (gold markers) may be used in SBRT to make it easier to guide the radiation to the tumor. The markers are usually placed during an out-patient procedure.


Brachytherapy (internal or implant radiation therapy) is radioactive material sealed in needles, seeds, wires or catheters is placed directly into or near a tumor. Brachytherapy allows a high dose of radiation to be placed near the tumor while avoiding nearby healthy tissue. It can also be used to help open an almost-blocked lung airway, to help stop bleeding or to increase the radiation dose in addition to regular external beam irradiation. This type of radiation generally requires anesthesia and an overnight hospital stay.

Radiation for brain cancer

Radiation is also used to treat lung cancer that has spread (metastasized) to the brain. It is also used to reduce the risk of the cancer spreading to the brain after successful treatment of small cell lung cancer.

There are several ways radiation is used to treat or prevent brain metastases:

  • Whole Brain Radiation is external beam photon radiation to the head to treat metastases. 3D-CRT is often used.
  • Hippocampal-Sparing Radiation (the hippocampus is located in the lower part of the brain) during whole-brain radiation is being studied as a way to minimize memory loss that can be a side effect of whole-brain radiation.
  • Stereotactic Radiosurgery (SRS) is similar to SBRT to other organs. It targets the tumor(s) to minimize side effects associated with whole-brain radiation. CyberKnife® and GammaKnife® machines are both used and each delivers treatment in 1-5 sessions.
  • Prophylactic Cranial Irradiation (PCI) is radiation to the head to reduce the risk of or prevent brain metastases. It is most commonly recommended after successful treatment for SCLC.
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