Stereotactic Radiosurgery (SRS) Uses Benefits Risks

In recent years, medicine has witnessed tremendous advancements in cancer treatment, making therapeutic options more precise and less surgically invasive. Among these modern techniques, Stereotactic Radiosurgery (SRS) stands out as one of the most advanced methods for treating brain tumors and certain other tumors without the need for a surgical incision.Although the term "surgery" is in its name, SRS does not involve any cuts or general anesthesia. Instead, it relies on delivering highly focused radiation doses directly to the tumor, while carefully preserving the surrounding healthy tissue.So, what exactly is stereotactic radiosurgery? How does it work? When do doctors recommend it? And what are its main benefits and potential risks? In this article from Dalily Medical, we answer everything you need to know about this modern medical procedure.

What is Stereotactic Radiosurgery (SRS)?

Stereotactic Radiosurgery (SRS) is an advanced, non-surgical treatment technique that delivers highly focused radiation doses to precise areas within the body, particularly brain tumors and certain tumors in other parts of the body.

Although the term “surgery” may suggest a traditional operation, this type of treatment does not involve any surgical incision or scalpel intervention. Instead, it relies on advanced imaging techniques to locate the tumor accurately and then targets it with radiation to destroy abnormal cells while minimizing damage to surrounding healthy tissue.

This technique is an effective option in cases where conventional surgery is difficult or risky.

Is SRS a real surgical procedure?

No. It is not surgery in the traditional sense:

No incisions are made.
General anesthesia is not required.
High-precision, focused radiation is used to target and destroy abnormal cells without direct surgical intervention.

Is SRS painful?

Generally, the procedure is painless.

Patients may experience minor sensations, such as:

Slight pressure if a head frame is used
Mild headache or fatigue after the session

During the treatment itself, patients do not feel actual pain.

How long does a session take?

The duration depends on the tumor’s size and location:

Typically ranges between 30 and 90 minutes
May extend to several hours in some cases
Some patients require a single session, while others may need multiple sessions

Does the radiation affect the whole body?

No. SRS delivers highly focused radiation directed only at the tumor, which means surrounding healthy tissues are minimally affected compared to conventional radiation therapy.

Does SRS cause hair loss?

In most cases, hair loss does not occur, because the radiation is precisely targeted at a very small area.

However, in certain cases, especially when the treated area is very close to the scalp:

Hair loss is limited to a small area
Often unnoticeable
Usually temporary, with hair regrowth within a few months

This depends on the radiation dose, treatment location, and equipment used, such as Gamma Knife, CyberKnife, or LINAC devices.

Is SRS safe?

Yes. SRS is considered one of the safest and most precise treatments for brain tumors and certain neurological disorders.

Reasons for its safety include:

No actual surgery or skull opening
No bleeding or surgical wounds
Very low risk of infection
Radiation precisely targets the tumor while protecting healthy tissues
Much lower complication rates compared to conventional surgery

Preparing for Stereotactic Radiosurgery (SRS)

Proper preparation is crucial to ensure treatment success and minimize potential side effects. Preparation involves medical and organizational steps that help the medical team perform the procedure safely and accurately.

1. Initial medical consultation

Preparation begins with a detailed consultation with a radiation oncologist. During this visit, the doctor:

Reviews the patient’s full medical history
Performs a general physical examination
Explains the SRS procedure and its steps
Outlines potential benefits and risks
Answers all patient questions

This step is essential for creating an individualized treatment plan.

2. Imaging and medical tests

Before treatment, patients undergo precise imaging to accurately locate the tumor, including:

Magnetic Resonance Imaging (MRI)
Computed Tomography (CT) scans

These tests allow the medical team to plan the radiation path precisely while protecting healthy tissue. Patients may be instructed to follow specific guidelines, such as fasting or avoiding certain medications.

3. Instructions before the procedure

Patients receive clear guidance, which may include:

Scheduling meals and fluids before treatment
Avoiding certain medications temporarily
Following any health-specific instructions

Following these instructions ensures safe and efficient treatment.

4. Reviewing current medications

Patients should inform their doctor about all medications, including:

Prescription drugs
Over-the-counter medications
Vitamins and supplements

Some medications, especially blood thinners, may need to be temporarily paused to reduce the risk of complications.

5. Arranging a companion for the treatment day

It is recommended to have someone accompany the patient to:

Provide emotional support
Assist with returning home
Stay with the patient if fatigue occurs after treatment

Although most patients can go home the same day, having a companion is a safety precaution.

6. Mental preparation and stress reduction

It is natural to feel anxious before the procedure. Stress can be reduced by:

Practicing deep breathing exercises
Relaxation or meditation
Discussing concerns with the doctor

Understanding the procedure helps increase reassurance.

7. What to expect on treatment day

On the day of SRS, patients are advised to:

Arrive early at the treatment center
Complete registration procedures
Wear hospital clothing if required
Follow medical team instructions

Indications for SRS

SRS is used to treat various brain tumors and certain neurological disorders, especially when conventional surgery is difficult or when precise radiation therapy is the safest and most effective option.

Factors influencing the decision include:

1. Tumor characteristics

SRS is recommended for tumors that are:

Small to medium-sized
Well-defined with clear borders
Located in sensitive or deep brain areas
Not widely spread across the brain

These features allow precise targeting while protecting healthy tissue.

2. Tumor type

SRS can treat multiple tumor types:

Primary brain tumors such as:

Gliomas
Meningiomas

Metastatic tumors (spread from other organs), including:

Lung cancer
Breast cancer

Benign tumors such as:

Acoustic neuromas
Pituitary tumors

SRS can halt tumor growth or reduce size without traditional surgery.

3. Patient’s overall health

SRS is particularly suitable for patients who:

Cannot undergo surgery due to age
Have chronic illnesses like heart or lung disease
Are at high risk from general anesthesia

In such cases, SRS provides a safe and effective alternative.

4. Symptoms caused by the tumor

SRS may be recommended if the tumor causes significant symptoms, such as:

Seizures
Persistent headaches
Weakness or loss of movement
Balance or vision problems

The treatment can shrink or control the tumor, alleviating symptoms.

5. Imaging results

Imaging studies like MRI or CT help evaluate:

Tumor size
Location
Shape and boundaries

If the tumor is clearly defined, the patient may be an ideal candidate for SRS.

6. Previous treatments

SRS can also be used:

After conventional surgery to remove residual tumor
For recurrent tumors
Following chemotherapy or conventional radiation therapy

In these cases, SRS acts as a complementary treatment to improve tumor control.

Types of Stereotactic Radiosurgery (SRS)

SRS techniques vary depending on the device used and the method of radiation delivery. All aim to deliver a high dose of radiation to the target while protecting surrounding healthy tissues.

1. Gamma Knife

This technique uses the Gamma Knife, which directs hundreds of concentrated gamma rays to converge on a precise point in the brain.

Advantages:

Extremely high precision for brain tumors
Suitable for arteriovenous malformations
Can treat multiple targets in one session
Mainly used inside the skull
Ideal for small to medium tumors in delicate brain areas

2. Linear Accelerator (LINAC)

LINAC uses high-energy X-rays directed precisely at the tumor.

Advantages:

Can treat tumors inside and outside the skull
Suitable for spine and other body tumors
Provides real-time imaging during treatment
Allows precise adjustments during the session
More versatile than Gamma Knife, especially for extracranial tumors

3. CyberKnife

CyberKnife combines a small linear accelerator mounted on a robotic arm, allowing radiation delivery from multiple angles.

Advantages:

Treats brain, spine, lung, and prostate tumors
No head frame required
Tracks tumor movement during patient breathing
High precision even with motion
Ideal for moving or hard-to-fix tumors

4. Fractionated Stereotactic Radiotherapy (FSRT)

FSRT delivers the radiation dose in multiple small fractions rather than a single session.

Advantages:

Suitable for larger tumors
Safer for tumors near sensitive tissues
Reduces side effects
Allows normal tissues time to recover between sessions

Methods of Performing Stereotactic Radiosurgery (SRS)

1. Gamma Knife

Preparation

MRI or CT scans are performed to precisely locate the tumor.
A special metal head frame is attached to ensure no movement during treatment.
The patient may be asked to fast for a few hours before the procedure.

During the Procedure

The patient lies inside the Gamma Knife device, which resembles a large helmet containing multiple radiation sources.
Gamma rays are directed from different angles, concentrating the dose only on the tumor.
Sessions usually last 30–60 minutes, depending on tumor size.

After Treatment

Hospitalization is usually not required.
Patients can resume daily activities the same day or the following day.

2. CyberKnife

Preparation

MRI or CT scans are used to locate the tumor.
Small markers may be placed on the body for precise targeting.
A head frame is usually not required.

During the Procedure

The patient lies on a treatment table.
A robotic arm moves around the body to deliver radiation from multiple angles.
The system tracks tumor movement in real time, particularly for lung or spinal tumors.
Sessions last approximately 30–90 minutes.

After Treatment

Patients can go home the same day.
Most resume normal daily activities quickly.

3. Proton Beam Radiosurgery

Preparation

Precise imaging (MRI and CT) is performed.
Special immobilization devices may be designed to protect healthy tissue.

During the Procedure

Proton beams are directed with high precision at the tumor.
Protons deliver radiation directly to the target with minimal effect on surrounding tissue.
Sessions may last 1 hour or more, depending on the case.

After Treatment

Patients can return home the same day.
Mild temporary fatigue may occur.

4. LINAC / X-ray Radiosurgery

Preparation

CT or MRI is used to locate the tumor.
The head is stabilized with a special mask or immobilization device.

During the Procedure

A linear accelerator delivers high-energy X-rays to the tumor.
Continuous imaging ensures precise targeting.
Sessions usually last 30–60 minutes.

After Treatment

Patients can quickly resume daily activities.
Mild temporary fatigue may occur.

5. Carbon Ion Radiosurgery

Preparation

MRI or CT imaging is performed for precise localization.
Immobilization devices are used to prevent movement.

During the Procedure

High-energy carbon ions are precisely directed at the tumor.
Effective for tumors resistant to conventional treatment.

After Treatment

Patients may experience mild fatigue or dizziness.
Daily activities can usually be resumed within a few days.

6. Dynamic Conformal Radiosurgery (DCRS)

Preparation

Imaging is done to define the tumor shape.
The patient is immobilized using special devices.

During the Procedure

The machine adjusts the direction and shape of radiation automatically during the session.
Allows precise targeting of moving tumors.

After Treatment

Rest for a few hours is recommended.
Daily activities can be resumed quickly.

Contraindications for SRS

Although SRS is safe and effective in many cases, it is not suitable for everyone. Situations where SRS should be avoided or alternative treatments considered include:

Very large tumors
- Tumors >3–4 cm are difficult to target precisely.
- Risk of damaging surrounding tissue and radiation toxicity increases.
Tumors near sensitive structures
- Near major nerves, large blood vessels, spinal cord, or critical brain areas.
- Risk of neurological deficits, memory loss, or motor problems.
Multiple tumors in different areas
- Difficult to target all tumors in a single session.
- May require higher doses or multiple sessions, increasing exposure to healthy tissue.
Poor general health
- Severe heart, lung, liver disease, or immunodeficiency.
- Higher risk of complications and reduced treatment effectiveness.
Inadequate tumor evaluation
- Difficulty precisely locating the tumor with imaging.
- Radiation may affect healthy tissues.
Tumors with large necrotic areas
- Dead tissue within the tumor does not respond to radiation.
Pregnancy
- SRS is generally avoided unless absolutely necessary.
- Risk of radiation affecting fetal development.
Tumors easily treated surgically
- Large or surgically accessible tumors may have better outcomes with conventional surgery.
Recurrent or rapidly growing tumors
- SRS may be less effective; alternative therapies like chemotherapy or immunotherapy may be needed.
Radiation hypersensitivity
- Some patients have syndromes that increase sensitivity to radiation.
- May require alternative treatments.

Risks and Complications of SRS

Even though SRS is highly precise, potential risks include:

Neurological complications
- Headache, nausea, dizziness, limb weakness or numbness
- Memory or cognitive problems
- Seizures in some cases
Radiation toxicity to healthy tissue
- Damage to non-cancerous cells
- Possible effect on nearby vital organs
- Skin irritation if the area is superficial
Localized swelling and damage
- Brain or treatment-area swelling
- Pain or pressure in the treated region
Long-term complications
- Increased risk of secondary cancers
- Gradual decline in neurological or sensory function
- Genetic effects on normal cells
Fatigue and exhaustion
- Severe tiredness affecting daily life
- General weakness requiring longer rest
Gastrointestinal effects
- Nausea and vomiting if tumors are near stomach or intestines
- Difficulty swallowing or throat irritation
Vascular effects
- Internal bleeding or blood clots
- High blood pressure if tumors are near major vessels
Psychological and emotional effects
- Anxiety, depression, stress
- Concerns about long-term treatment impact
Infections
- Inflammation or infections near the treated area
Fertility effects
- Possible temporary or permanent fertility issues if tumors are near reproductive organs

Recovery After SRS

Recovery depends on tumor size, treated area, and patient’s health but generally follows these stages:

1. Immediate Recovery (Right after the session)

Most patients resume daily activities within hours or the next day.
Rest for a day or two is recommended to reduce fatigue or mild symptoms like headache or nausea.

2. Initial Symptoms (First few days)

Headache and nausea may last from a few hours to a few days.
Temporary fatigue and dizziness are common.

3. Temporary Side Effects (First weeks)

Swelling or inflammation may last a few days to two weeks for sensitive areas.
Fatigue can persist for 1–2 weeks depending on tumor size and location.

4. Medium-term Recovery (1–3 months)

Gradual improvement in fatigue and headaches after 4–6 weeks.
Neurological symptoms such as weakness or numbness often improve.
Regular follow-ups are recommended to monitor tumor or side effects.

5. Full Improvement (3–6 months)

Most temporary neurological symptoms gradually resolve.
Tumor begins to shrink, monitored via MRI or CT scans.

6. Long-term Follow-up (6 months and beyond)

Patients are monitored for tumor recurrence for 1–3 years.
Complete recovery from fatigue or neurological effects may take longer, but most return to normal life within 6–12 months.