Stereotactic Radiosurgery (X-Knife / SRS)

Overview

Stereotactic radiosurgery (SRS), delivered by systems such as the X-Knife, is a highly precise, non-invasive treatment that focuses many beams of high-energy radiation onto a small target from many directions. Where the beams converge, they deliver a powerful dose to the tumour or lesion, while each individual beam passes through healthy tissue with little effect.

Despite the word "surgery," there is no incision. SRS is used mainly for small, well-defined targets in the brain, and related stereotactic body radiotherapy (SBRT) treats small tumours in sites such as the lung, spine and liver. It offers an alternative to conventional surgery for selected patients and tumours.

This page is an educational overview only and is not medical advice. Whether radiosurgery is suitable can only be decided by a specialist radiation oncology and neurosurgical team, and no outcome can be guaranteed.

Who May Need This

SRS may be considered for people with small brain tumours, including certain metastases from cancer elsewhere and some benign tumours such as acoustic neuromas (vestibular schwannomas) and meningiomas, as well as abnormal blood vessel tangles called arteriovenous malformations. Body stereotactic radiotherapy may suit small, localised tumours in patients who cannot have, or prefer to avoid, surgery.

Suitability depends on the target's size, shape, location and type, and on the person's overall health and previous treatments. A multidisciplinary team assesses whether radiosurgery, conventional surgery, standard radiotherapy or another approach is the best option.

When It May Be Recommended

Radiosurgery may be recommended when a target is small and well-defined but difficult or risky to remove surgically, when a patient is not fit for open surgery, or as a focused treatment for a limited number of brain metastases. It is also used for some benign tumours and vascular malformations where precise, tissue-sparing treatment is valuable.

The decision weighs the benefits of a non-invasive approach against the fact that radiosurgery controls or shrinks a target over time rather than removing it immediately. It considers alternatives such as surgery, whole-brain radiotherapy or drug treatment. The recommendation is made after full assessment.

Diagnosis and Evaluation

Evaluation includes high-quality imaging — usually MRI for brain targets, sometimes combined with CT and, for some tumours, other scans — to define the target precisely. The type of lesion is established from prior biopsy, surgery or characteristic imaging, and its size and relationship to critical structures are carefully assessed.

A specialist team, typically including a radiation oncologist, neurosurgeon and medical physicist, reviews whether radiosurgery is appropriate and designs a plan. Blood tests and a review of general health and other treatments complete the work-up. A second opinion may be helpful before deciding.

Treatment Options

Focused radiation options include linac-based systems such as the X-Knife and CyberKnife, and cobalt-based Gamma Knife for the brain, as well as stereotactic body radiotherapy (SBRT) for tumours elsewhere. Treatment may be a single session (radiosurgery) or a small number of sessions (fractionated stereotactic radiotherapy).

These options are compared with conventional surgery, standard radiotherapy and drug treatments depending on the tumour. For brain metastases, for example, the choice between focused radiosurgery and whole-brain radiotherapy depends on the number and size of the lesions. The team selects the most suitable approach.

How It Is Performed

For brain radiosurgery, the head is kept precisely still using either a lightweight frame fixed to the skull or a custom mask, and detailed imaging is used to plan the exact target. During treatment, which is painless, the machine directs many focused radiation beams that converge on the target while you lie still; a session may take from several minutes to around an hour.

Body stereotactic radiotherapy uses moulds, image guidance and sometimes techniques to account for breathing movement, delivering focused radiation in a few sessions. Most patients go home the same day. There is no incision and no anaesthetic for the radiation itself, though frame placement uses local anaesthetic.

Preparation

Preparation includes attending planning imaging and, for masked treatments, having a custom mask made. You may be asked to stop certain medicines or adjust steroids as advised, and to arrange transport home. Your team explains the process, the number of sessions and what to expect on the day.

If you are travelling for treatment, bring your imaging and records, including details of any previous radiotherapy to the area. Plan an in-country stay to cover planning and treatment sessions and a follow-up review, and arrange ongoing imaging and follow-up with your home team.

Benefits and Expected Goals

The goals of radiosurgery are to control or shrink the target, relieve or prevent symptoms, and preserve surrounding healthy tissue, all without an incision, a hospital stay or a general anaesthetic in most cases. For suitable targets it offers precise treatment with a quick recovery.

The effect develops over weeks to months rather than immediately, and benefits depend on the type, size and location of the target and cannot be guaranteed. Your team can explain the realistic goals — such as tumour control, symptom relief or reducing recurrence — for your specific situation and how response will be monitored.

Risks and Possible Complications

Radiosurgery is generally well tolerated, but it is not risk-free.

• Temporary tiredness, headache or nausea after brain treatment
• Swelling around the target (oedema) that may need steroids
• Radiation effects on nearby structures, depending on location (for example, effects on nerves, hearing or vision)
• Delayed changes such as radiation necrosis in a minority of patients
• Incomplete control or regrowth requiring further treatment

Your team will explain the specific risks based on the target's location and the dose. Report severe or worsening headache, new neurological symptoms or seizures promptly.

Recovery, Follow-up & Aftercare

Because it is non-invasive, recovery is usually quick, and many people return to normal activities within a day or two, sometimes with short-lived tiredness or headache. If a frame was used, the small pin sites are cared for as advised. Steroids may be prescribed for a short time to manage swelling.

Follow-up centres on imaging (usually MRI) over the following months to assess whether the target has responded, along with clinical review. If you were treated abroad, arrange this imaging follow-up with your home team and carry a summary of the treatment, including the target and dose.

Medical Tourism Planning

Choose a JCI- or ISO-accredited hospital with a dedicated stereotactic radiosurgery programme, experienced radiation oncologists, neurosurgeons and medical physicists, and modern planning and delivery equipment. Confirm that your tumour is suitable and the plan (system, number of sessions) in writing.

Plan an in-country stay covering planning, treatment and a review, and arrange follow-up imaging with your home team, since the response is assessed over months. Carry a full treatment summary home and consider medical travel insurance.

Estimated Cost Factors

Cost depends on the system used, the number of sessions, the planning and imaging required, and whether it is combined with surgery or drug treatment. The complexity of the target and the need for follow-up imaging also affect the total.

Many destinations offer stereotactic radiosurgery at a fraction of typical US prices, but costs vary by system and plan and cannot be judged from online figures. Always request a personalized written quote detailing what is included before deciding.

Choosing a Hospital or Specialist

Look for a hospital with recognised accreditation, an established radiosurgery service with strong medical physics and quality assurance, and a multidisciplinary team including radiation oncology and neurosurgery. Confirm the team's experience with your type of target and the equipment available.

Ask about international patient services, interpreter support, and how follow-up imaging and any further treatment would be coordinated with your home doctors. Written treatment and cost plans are signs of a quality programme.

Alternatives

Alternatives to radiosurgery include conventional surgery to remove a tumour, standard or whole-brain radiotherapy, and drug treatments such as chemotherapy, targeted therapy or immunotherapy, depending on the diagnosis. For some benign lesions, monitoring may be appropriate.

The best choice depends on the target's size, number, location and type, and on the person's overall health. Each option has different benefits, risks and recovery. Discuss all of them with your specialist team so the plan fits your situation and priorities.

Questions to Ask Your Doctor

• Is my tumour or lesion suitable for stereotactic radiosurgery, and why?
• Would surgery or conventional radiotherapy be better in my case?
• Will treatment be a single session or several, and which system will you use?
• What results can I realistically expect, and how soon?
• What are the specific risks given the target's location?
• What follow-up imaging will I need, and when?
• If I travel, how will follow-up be arranged with my home team?
• What is included in the written cost estimate?