What Radiation Is Used in Gamma Knife Radiation?

Medical professionals use several types of radiation in medical testing and treatment. X-rays, gamma rays, and other forms of ionizing radiation are used to diagnose and treat various medical conditions. This can be radiation that penetrates from outside the body, or radioactive particles that are ingested or inserted into the body.

Imaging tests, such as x-rays, CT scans, and nuclear medicine tests, expose people to low levels of radiation in order to create internal pictures of the body. 

Gamma rays and other ionizing radiation treatments are used to kill abnormal cells in some patients. This method has produced excellent results for many people, particularly those with brain tumors, while minimizing the negative side effects. This is the radiation used in Gamma Knife radiation therapy, or Gamma Knife radiosurgery. 

Gamma Knife Radiation

Gamma knife radiation therapy treats patients by using gamma rays, which have the most energy and smallest wavelengths of any wave in the electromagnetic spectrum. Radioactive atoms and nuclear explosions produce these rays which can easily kill living cells, including cancer cells.

Gamma Knife is not surgery in the traditional sense because it does not involve an incision. Instead, sophisticated equipment focuses approximately 200 rays of gamma radiation at the tumor or other abnormalities, such as misfiring nerves and tangled blood vessels. This procedure also treats Parkinson’s, epilepsy and other conditions. 

This process treats the “bad” tissue while preserving the surrounding healthy tissue. As a result, Gamma Knife treatment has fewer side effects than traditional radiation treatments. This procedure is much less harmful to the body than traditional surgery, particularly brain surgery.

Side Effects of Gamma Knife Radiation

Gamma knife radiation therapy usually takes place as an outpatient procedure, allowing you to return home quickly after the process is completed. You may have a little pain and swelling where the doctor places a frame to steady your head, but that rarely lasts long. Other side effects generally resolve in a matter of days or a few weeks and include:

  • Fatigue
  • Red, irritated skin
  • Headaches
  • Nausea and vomiting
  • Possible hair loss around the treatment area


Long-term side effects are rare, but if you experience lingering issues, you should discuss them with your surgeon.


Many patients can return to work in a day or two and resume other daily activities then as well. You may notice an immediate difference in your health, but you should also see a gradual improvement in your condition over the coming weeks and months. You will be carefully monitored by your physician who will assess your progress and other medical conditions as well.

Traditional brain surgery takes a more severe physical toll and may keep most patients from regular activities for several months. 

Next Steps

Before proceeding with Gamma Knife radiosurgery, you should do your research and consult with experts in the procedure. If you would like to learn more about Gamma Knife radiosurgery as a treatment option for you, contact the Valley Gamma Knife Center and a Nurse Navigator will be glad to speak to you about possible next steps.

Anthony D’Ambrosio, M.D., M.B.A., F.A.A.N.S
Anthony D’Ambrosio, M.D., M.B.A., F.A.A.N.S
Dr. Anthony D’Ambrosio is a board-certified neurosurgeon that specializes in Neurosurgery, Stereotactic Radiosurgery, Gamma Knife Radiosurgery (GKRS) and more. He is the Director of Neurosurgery and Co-Director of the Gamma Knife Program at The Valley Hospital. Dr. D’Ambrosio is an expert in treating patients with trigeminal neuralgia, benign or malignant brain tumors, as well as many other neurological conditions.

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