GAMMA KNIFE
RADIOSURGERY FOR BRAIN TUMOURS
192 beams of radiation converging on a tumour with sub-millimetre accuracy — no incision, no anaesthesia, and no hospital stay in most cases.
analyticsAt a Glance
- check_circleTreats brain metastases, meningiomas, acoustic neuromas, pituitary tumours, and AVMs without open surgery
- check_circleSingle-session treatment for most patients — 1–3 hours, outpatient
- check_circleSub-millimetre accuracy using stereotactic frame or mask — surrounding brain tissue receives minimal radiation
- check_circleCancerFax identifies Gamma Knife centres in China and India and coordinates access and pre-treatment planning review
What Is Gamma Knife Radiosurgery?
Gamma Knife is not a knife in the surgical sense — it delivers no incision, no anaesthesia, and no hospital stay. It is a stereotactic radiosurgery platform that uses 192 sources of cobalt-60 gamma radiation, all converging on a single point in the brain with sub-millimetre precision.
“At the target, the dose is ablative. Millimetres away, it is near zero. This is the principle that makes Gamma Knife safe in the brain — precision that open surgery cannot match.”
How It Works
192 cobalt-60 sources arranged in a hemispherical helmet each emit a low-dose gamma ray beam. Each beam alone cannot damage tissue — but where all 192 converge, the dose is high enough to destroy tumour cells, permanently damage tumour blood vessels, and halt growth.
What Makes It Different from Regular Radiotherapy?
Standard radiotherapy delivers dose in daily fractions over weeks — Gamma Knife delivers a precise ablative dose to a defined target in a single session. The steep dose fall-off means normal brain tissue 5–10 mm beyond the target receives very low radiation.
What Brain Tumours and Conditions Does Gamma Knife Treat?
Gamma Knife is used across a wide range of intracranial conditions — from common brain metastases to rare vascular malformations. Each indication has an established evidence base.
| Condition | Role of Gamma Knife | Evidence Level |
|---|---|---|
| Brain metastases (1–4 lesions) | Primary treatment — replaces WBRT in most guidelines | Level 1 — multiple phase III RCTs |
| Brain metastases (5–10 lesions) | Active at specialist centres — JLGK0901 data supports | Level 2 — prospective cohort |
| Meningioma (grade 1, small–medium) | Primary or adjuvant after subtotal resection | Level 2 — large prospective series |
| Acoustic neuroma (vestibular schwannoma) | Primary treatment — 95%+ tumour control, hearing preservation in many | Level 2 — long-term cohort studies |
| Pituitary adenoma | Adjuvant after surgery for residual/recurrent disease | Level 2 — endocrine outcomes data |
| AVM (arteriovenous malformation) | Obliteration of small–medium AVMs — 80%+ obliteration at 3 years | Level 2 — prospective registry |
| Trigeminal neuralgia | Radiation to the trigeminal nerve root — pain relief in 70–85% | Level 2 |
| Recurrent glioma | Re-irradiation at progression — selected cases | Level 3 — retrospective series |
What to Expect on Gamma Knife Treatment Day
A standard single-fraction Gamma Knife session takes 4–8 hours from arrival to discharge — most of which is planning and positioning, not radiation delivery.
- 1
Frame or Mask Fitting
A stereotactic frame is attached to the skull under local anaesthesia (4 small pins) to provide immobilisation and a coordinate system for targeting. Frameless mask systems are used for fractionated treatments.
- 2
MRI/CT Planning Scan
A planning MRI (with gadolinium) is acquired with the frame in place. The images are transferred to the GammaPlan treatment planning system where the radiosurgeon defines target volumes and dose prescription.
- 3
Dose Planning
The neurosurgeon, radiation oncologist, and physicist collaboratively design the treatment — defining isodose lines, ensuring adequate tumour coverage, and keeping dose to optic nerves, brainstem, and cochlea within tolerance.
- 4
Radiation Delivery
Patient positioned in the Gamma Knife unit. Multiple isocentre irradiations are delivered automatically. The patient is awake throughout — no anaesthesia. A single metastasis may take 15–30 minutes; multiple lesions take longer.
- 5
Recovery and Discharge
Frame removed after treatment (brief local anaesthetic). Patient observed for 1–2 hours for headache or nausea, then discharged home the same day. No overnight admission required in most cases.
Gamma Knife Efficacy — Key Numbers
Local control rates for Gamma Knife across its major indications are consistently high — comparable to surgery in most settings, without the surgical morbidity.
- 80–90%Local control at 1 year — brain metastasesAcross multiple prospective series and RCTs for lesions <3 cm treated with standard SRS doses (20–24 Gy marginal).
- 95%Tumour control — acoustic neuroma at 5 yearsLong-term hearing preservation in 50–60% of patients with serviceable hearing at baseline.
- ~80%AVM obliteration at 3 years (small AVMs)For AVMs <3 cm, 3-year obliteration rate is ~80%. Larger AVMs may require staged treatment or combined embolisation.
Gamma Knife vs Open Surgery — When to Choose Which
For many brain lesions, Gamma Knife and surgery are both effective options. The choice depends on lesion size, location, need for tissue diagnosis, and patient fitness for surgery.
Gamma Knife (Preferred When…)
- Lesion <3 cm and deep/eloquent locationDeep lesions (thalamus, basal ganglia, brainstem) or those in eloquent cortex are high-risk for surgery — Gamma Knife achieves control without surgical risk.
- Multiple lesionsWhen 2–4 lesions are present, treating all with SRS is less morbid than craniotomies for each.
- Patient not fit for general anaesthesiaGamma Knife requires only local anaesthesia — it is appropriate for elderly patients or those with medical comorbidities.
Open Surgery (Preferred When…)
- Lesion >3–4 cm with significant oedema/mass effectLarge lesions causing significant oedema and herniation risk require surgical decompression — SRS alone does not provide immediate mass effect relief.
- Tissue diagnosis requiredUnknown primary, atypical imaging features, or need to determine pathology to guide systemic therapy — surgery provides the tissue.
- Recurrent lesion after prior SRSRadiation necrosis vs true recurrence can only be definitively distinguished by surgical resection — and surgery is required for recurrent disease in prior SRS field.
Frequently Asked Questions
Practical questions from patients preparing for Gamma Knife radiosurgery.
Is Gamma Knife radiosurgery painful?
The frame attachment involves four small pins under local anaesthesia — patients describe it as minimal discomfort, similar to a dental procedure. The radiation delivery itself is painless. A headache may occur after frame removal, manageable with simple analgesia.
How long does it take to see if Gamma Knife worked?
Response is assessed on follow-up MRI at 6–8 weeks and then every 3 months. Brain metastases often show initial enlargement (pseudo-progression) at 4–8 weeks before shrinking — this can be confused with treatment failure. Specialist neuro-radiology review is essential to interpret post-SRS imaging correctly.
What is radiation necrosis and how common is it after Gamma Knife?
Radiation necrosis is an inflammatory response to SRS, seen in 5–15% of treated lesions at 1–2 years. It appears as contrast-enhancing tissue on MRI and can be difficult to distinguish from tumour recurrence. Most cases are managed with steroids; some require bevacizumab; surgical resection is reserved for symptomatic cases not responding to medical management.
How much does Gamma Knife cost in India vs China vs the US?
In India, a single-session Gamma Knife treatment for 1–3 brain metastases costs approximately ₹1.5–3 lakh ($1,800–3,600 USD) at major centres like AIIMS, Fortis, or Apollo. In China (top centres in Beijing/Shanghai), costs range from RMB 30,000–80,000 ($4,200–11,000 USD). In the US, the same procedure costs $15,000–30,000 USD. CancerFax can provide detailed cost estimates for specific centres.
More from the Brain Tumour Treatment Guide
Explore related guides on brain tumour treatment options, comparisons, and specialist access.
How CancerFax Helps
CancerFax is a specialist cancer access and patient-navigation platform. We help patients and families understand their options, organise medical records, coordinate hospital communication, and support cross-border treatment planning where appropriate.
We help collect and organise reports, scans, pathology, biomarker results, and treatment history for structured case review.
We communicate with hospitals or trial teams to assess whether a case may be suitable for further screening.
We support appointment coordination, document submission, translation, and direct communication with international departments.
For international patients, we help with practical coordination — travel planning, hospital admission guidance, and local support.
If this option is not suitable, we help explore other relevant treatments, clinical trials, or advanced care pathways.
From inquiry through to follow-up, our coordinators provide a single point of contact for the family.
CancerFax does not guarantee treatment access, eligibility, or clinical outcome. Our role is to help patients access accurate information, structured review, and appropriate specialist pathways.
Is Gamma Knife the Right Treatment for Your Brain Tumour?
CancerFax reviews your MRI brain, pathology, and tumour characteristics to assess whether Gamma Knife radiosurgery is the appropriate treatment — and connects you with the right centre in China, India, or internationally for treatment planning and delivery.
This content is for informational purposes only and does not constitute medical advice. Always consult a qualified oncologist before making treatment decisions.