Stereotactic Radiosurgery (SRS)
Stereotactic radiosurgery (SRS) is surgery in name only. Nothing is cut: a radiation oncologist aims precise, high-dose beams at a small target in the brain or spine, usually in one to five sessions. Wondering whether it could stand in for an operation in your case? This page explains how SRS works, who it suits, and what treatment day feels like.
Reviewed by Dr. P. Vijay Karan Reddy · Radiation Oncologist ·
Last updated October 2026
Stereotactic radiosurgery (SRS) is radiation therapy that delivers a high dose to a small, clearly defined target in the brain or spine, with no incision. It's completed in one to five sessions and is used for small benign tumours, brain metastases and some non-cancer conditions. The same approach applied to tumours elsewhere in the body is called SBRT.
What Is Stereotactic Radiosurgery? Surgery Without a Scalpel
Picture a small tumour sitting beside the area that controls speech. An operation means opening the skull near it. SRS reaches the same spot through the skin, using many thin beams that cross at the tumour. Each beam alone has little effect on the tissue it passes through. Where they meet, the dose is enough to stop the tumour's cells dividing.
The name misleads people. "Stereotactic" means the target is pinpointed in 3D coordinates, and there's no cutting, as Mayo Clinic notes. Dr. Karan, a radiation oncologist, plans and delivers the radiation. If an operation is also part of your plan, as with a single brain metastasis, the partner surgical team performs it.
Stereotactic Radiosurgery Procedure: How SRS Works
SRS pins the target in 3D: your head is held still, MRI and CT are merged, and beams converge from many angles.
SRS by Condition: Who Is a Candidate
SRS suits small, clearly defined targets. These are the situations where Dr. Karan uses it.
Key Benefits of Stereotactic Radiosurgery
These are advantages, not guarantees: results depend on the lesion's size, number and location, and cost on the system and sessions.
Stereotactic Radiosurgery vs. Other Options
SRS isn't the only way to treat a brain or spine target. Here's how it differs from open surgery, whole-brain radiotherapy and SBRT, and where each fits.
SRS vs. open brain surgery
Surgery removes the tumour, gives a tissue diagnosis and relieves pressure fast when a tumour is large. SRS needs no incision and suits small, well-defined targets. Dr. Karan's view: for a small lesion, ask whether SRS can do the job before assuming surgery is the only route. Surgery is invasive and SRS isn't, so the options should always be discussed.
SRS vs. whole-brain radiotherapy
Dr. Karan chooses by count: up to five lesions get SRS, more than five get whole-brain radiotherapy. In a 2016 JAMA trial of people with one to three metastases, SRS alone protected memory and thinking better than adding whole-brain radiation, with similar survival.
SRS vs. SBRT
SRS treats the brain and spine in one to five sessions. SBRT uses the same precision for tumours in the body, such as the lung or liver. Same idea, different sites, and each has its own page.
Preparing for Stereotactic Radiosurgery
Most SRS preparation fits into one planning visit: a scan, a mask or frame, and a few health questions.
Gamma Knife, Linac and CyberKnife: Systems That Deliver SRS
Three platforms deliver most SRS. Dr. Karan's centre uses linac-based SRS on its TrueBeam STx with HyperArc, the same machine used for the rest of his radiation.
What a Treatment Day Looks Like
- 01
Check-in
You arrive at Apollo Hospital, Financial District. With waiting time, a visit usually takes 60 to 90 minutes, so bring someone along to keep you company and take you home.
- 02
Fitting and imaging
Your mask or frame is fitted. A scan then confirms the target's exact position, and the team corrects any small difference.
- 03
Beam delivery
Beams arrive from many angles while you lie still. It's painless, and the team can hear you over the intercom.
- 04
Time on the table
You're on the table for up to 15 minutes, and with about 30 to 45 minutes of waiting the whole visit takes around 60 to 90 minutes. Your plan sets the number of sessions.
- 05
Going home
The mask or frame comes off, and any pin sites are dressed. Most people go home the same day.
Stereotactic Radiosurgery Side Effects and Recovery
Is it really gentler than other radiation? Usually, because the dose is tightly focused. Most effects are mild and temporary.
Short-Term Effects
Tiredness for a few weeks is common. Some people get a headache, nausea or a tender scalp where the mask or frame sat, and a small patch of hair can thin. Medicines settle most symptoms.
Long-Term Effects
Uncommonly, months later, an area of swelling or tissue change (radiation necrosis) appears, and steroid medicines often settle it. Follow-up MRI scans catch it early. Risk depends on the target's size, location and dose.
Recovery and Results
Most people return to light routines within days. Cancers often shrink within a few months, while benign tumours can take 18 months to two years, so scans keep tracking the result.
Considering SRS? Get a Second Opinion First
Not sure SRS is the right fit, or whether surgery or whole-brain radiotherapy would serve you better? Send your MRI and reports. Dr. Karan will look at the number, size and position of the lesions, explain each option plainly, and say what he'd recommend. He brings eleven years in radiation oncology to every review.
What Happens After Treatment
SRS works slowly on brain lesions, often over months. Here's the general roadmap, not a personal schedule.
Timing depends on whether a benign tumour or a metastasis was treated, and on your recovery. Your MRI schedule is agreed with you before treatment ends.
Questions Patients Ask Us
No, you won't feel the beams; any discomfort comes from the mask or frame, and the scalp is numbed before a frame is fitted.
SRS gives a high dose to a small target in one to five sessions. Conventional radiotherapy spreads a lower dose over a wider area across several weeks.
Many small brain lesions need a single session; larger ones, or those near the optic nerves or brainstem, are often split into three to five.
It depends on the system, the number of sessions and the hospital, so there's no single price. At Dr. Karan's centre, a course of SRS costs ₹3 lakh.
It depends on your policy. SRS is an established treatment, so ask the billing desk to seek pre-authorisation with your MRI reports before your treatment date.
Stereotactic radiosurgery in India is offered at many major cancer centres. Dr. Karan plans and delivers SRS at Apollo Hospital, Financial District, Hyderabad.
It depends on the condition, size and location. For small acoustic neuromas, a benign tumour, a 2026 Cureus review reports that about 9 in 10 stop growing for 10 years or more, so most never need an operation.
It's a well-established treatment, and serious complications are uncommon. Your team will go through the risks for your target before you consent.
Not necessarily: protons are a type of radiation, while SRS is a way of aiming it at a small target. Dr. Karan uses protons mainly for children and says affordability is the main limit.
At most a small patch, and usually only where the beams entered. It typically regrows within a few months.
Find Out Whether SRS Fits Your Case
Send your MRI and reports, and Dr. Karan will tell you whether radiosurgery suits your lesion, how many sessions it would take, and what each one involves. No pressure, just a clear answer.
Written & reviewed by Dr. P. Vijay Karan Reddy ·
Radiation Oncologist · Last reviewed October 2026