Are There Any Side Effects of Gamma Knife Radiosurgery?

Gamma Knife radiosurgery is a minimally invasive, non-surgical option for patients with certain conditions of the head, neck and brain. If you’re considering Gamma Knife radiosurgery as a treatment for your condition, you’re probably curious about the possible side effects. The below outlines the immediate and delayed side effects of Gamma Knife in detail. 

How Gamma Knife Radiosurgery Works

To have a clearer picture of possible side effects that may come with Gamma Knife radiosurgery, it’s important to understand the way the procedure works. Despite the words “knife” and “surgery”, this procedure doesn’t involve either. Instead, Gamma Knife radiosurgery uses around 200 individual beams of high-dose radiation that are all focused on the area in need of treatment. While each beam on its own is not particularly potent, when used with the other beams, it delivers what is called a “therapeutic dose” of radiation. This means that the radiation created at the target is high enough to effectively damage and destroy the offending cells.

Side Effects of Gamma Knife Radiosurgery

While the potential side effects often associated with traditional surgery are avoided, such as infection, incision/surgical site pain, swelling, etc., Gamma Knife radiosurgery can have some potential side effects. Some of these appear shortly after the procedure, while others may take longer to occur. Luckily, any side effects of Gamma Knife radiosurgery tend to be mild in comparison to those of their surgical counterparts. 

Immediate Side Effects

Most immediate side effects of Gamma Knife are mild and resolve within a few days after you’ve undergone treatment. The most common immediate side effects include:

Swelling and Soreness of the Scalp

This is due to the irritation at the points on the scalp where the headframe was secured. In most instances, this will heal up and go away within a few days. If you have sensitive or easily irritated skin, let your surgeon and his or her team know so that they can take measures to minimize potential swelling and discomfort.


Many people report having mild-to-moderate headaches following their Gamma Knife radiosurgery treatment. This usually goes away within 24 to 48 hours.

Reddening and Irritation of Skin Within the Treatment Areas

This is not a particularly common side effect but has been reported. If you experience reddening and/or irritation, call your neurosurgeon’s office to find out what the best course of action is.


While rare, nausea can occur post-procedure. Talk to your doctor ahead of time about ways to address severe nausea that may arise from your Gamma Knife radiosurgery.


Seizures in Gamma Knife patients are very rare, but they can sometimes occur. If you have epilepsy, have ever had a seizure or are worried about this potential side effect, make sure your care team is aware of your concerns and takes any necessary precautions.

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Delayed Side Effects

The delayed side effects of Gamma Knife are a less common occurrence, but some patients do still experience the following complications. These can include:

Hair Loss

Hair loss can occur as a temporary side effect in localized and superficial lesions. Some patients report experiencing scalp soreness prior to their hair coming out. In the vast majority of cases, the hair will grow back fairly quickly.

Localized Brain Swelling

Temporary localized brain swelling can occur at the treatment site, but it is quite uncommon. If you suspect you are experiencing brain swelling, consult your doctor right away.

Numbness in the Face

In some instances, people that have undergone Gamma Knife radiosurgery for conditions such as trigeminal neuralgia may experience some numbness in their face, directly related to the part of the nerve that was treated. In some cases, this numbness will resolve, while in others it can be permanent.

Final Thoughts

Although the above side effects of Gamma Knife sound intimidating, most of them happen in only a small percentage of patients. The benefits of Gamma Knife radiosurgery far outweigh the risks for most. Be sure to talk to your doctor prior to your procedure to ensure you fully understand both the risks and benefits of this lifesaving treatment.

If you are interested in determining if Gamma Knife is a possible 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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