1. Overview

Stereotactic Radiosurgery (SRS) is a highly precise form of radiation therapy. It delivers a single high dose or a few very high doses of radiation to small, well-defined targets in the brain or head and neck area.

Despite the name “surgery,” SRS does not involve any incision. It uses advanced technology to focus hundreds of tiny radiation beams on the target from many different angles. The beams meet at the tumor with pinpoint accuracy, damaging cancer cells while minimizing harm to surrounding healthy brain tissue.

SRS is commonly delivered using machines such as Gamma Knife, CyberKnife, or modified linear accelerators. Treatment is usually completed in one session, though some cases use 2–5 fractions.

It is a powerful tool for treating tumors and other conditions inside the skull.

Read also: Stereotactic Body Radiation Therapy (SBRT)

2. Why is it done, and when is it chosen over other modalities

Doctors recommend Stereotactic Radiosurgery for conditions that need very high precision in sensitive areas like the brain.

Common reasons SRS is used:

• Brain metastases (cancer that has spread to the brain from elsewhere)

• Benign tumors such as meningiomas, acoustic neuromas (vestibular schwannomas), and pituitary adenomas

• Arteriovenous malformations (AVMs)

• Trigeminal neuralgia (severe facial pain)

• Certain primary brain tumors like gliomas in specific situations

When doctors choose SRS over other options:

• For small to medium-sized lesions (usually less than 3–4 cm)

• When the tumor is in a location where open surgery carries high risk

• When the patient prefers a non-invasive approach with quick recovery

• For patients who are not good candidates for traditional surgery due to age or other health conditions

Comparison with other modalities:

• Vs. SBRT: SRS is typically for the brain or head, while SBRT is used for tumors in the body (lung, prostate, liver, etc.). SRS often uses a single session.

• Vs. Conventional Whole Brain Radiation: SRS targets only the visible tumor(s) and spares more healthy brain tissue, reducing long-term side effects.

• Vs. Traditional Surgery: Offers similar local control without the risks of open brain surgery and with shorter recovery time.

SRS is selected when maximum precision and minimal damage to critical brain structures are essential.

3. Side effects of treatment

Side effects from SRS are generally mild compared to older radiation techniques, but they can still occur.

Early side effects (appear during or in the first few weeks):

• Headache

• Fatigue

• Temporary swelling around the treated area

• Nausea or dizziness (especially if the tumor is near balance centers)

• Hair loss in small patches (if near the scalp)

Late side effects (may appear months to years later):

• Radiation necrosis (dead tissue forming around the treated area)

• Persistent headaches or neurological changes

• Seizures (rare)

• Cognitive changes (less common than with whole brain radiation)

• Damage to nearby nerves (e.g., hearing loss with acoustic neuroma treatment)

Your medical team uses steroids and careful planning to reduce swelling and other risks. Most patients tolerate SRS very well.

4. How to prepare before the treatment

Patient Segment

• Follow all instructions about medications (especially blood thinners)

• Wash your hair with mild shampoo before the procedure

• Avoid hair products, makeup, or jewelry on treatment day

• Arrange for someone to drive you home after treatment

• Eat a light meal unless told to fast

• Bring a list of your current medications and allergies

• Discuss any anxiety with your doctor — mild sedation is sometimes used

Doctor / Medical Team Segment

• Perform detailed imaging (MRI, CT) for precise target mapping

• Create a custom head frame or use a frameless mask system for immobilization

• Develop a highly detailed 3D treatment plan

• Conduct quality assurance checks on the equipment

• Coordinate with neurosurgeons, radiation oncologists, and medical physicists

Preparation ensures the radiation hits only the intended target.

5. What to expect

Before treatment

You will have a simulation or planning visit. For frame-based SRS, a lightweight head frame is attached under local anesthesia. For mask-based systems, a custom thermoplastic mask is molded to your face. Imaging follows to finalize the plan.

During treatment

• You lie on the treatment table with your head securely positioned.

• The machine delivers radiation from multiple angles.

• You remain awake and can communicate with the team.

• Treatment time varies: 15 minutes to a few hours depending on complexity.

• Most single-session SRS treatments finish in under 2 hours.

Number of sessions: Many patients complete SRS in 1 session. Some receive treatment over 3–5 sessions (called fractionated SRS).

After treatment

You are monitored for a short time and can usually go home the same day. Rest is recommended for the remainder of the day. Most people return to normal activities within 1–3 days.

6. Expected results of the procedure

Stereotactic Radiosurgery provides excellent local control for many conditions.

• For brain metastases, SRS effectively controls treated lesions in 80–90% of cases.

• For benign tumors like meningiomas and acoustic neuromas, long-term control rates are very high (often above 90%).

• AVMs can be successfully obliterated over time.

• Pain relief for trigeminal neuralgia occurs in a large percentage of patients.

Many patients experience tumor shrinkage or stabilization over months. Because SRS is precise, it helps preserve brain function and quality of life better than older methods.

Results depend on the size, location, and type of the target. Your doctor will discuss realistic expectations for your specific case.

7. Call to Action

If you or a loved one has been diagnosed with a brain tumor, metastasis, or related condition, Stereotactic Radiosurgery (SRS) could be an excellent treatment option.

Book an appointment with a radiation oncologist or neurosurgeon experienced in SRS to learn if this advanced technique is suitable for you.

For more personalized information and to discuss your imaging and treatment options, contact our specialized team today. Getting expert advice early can make a significant difference in your care journey.