Stereotactic radiotherapy to the brain

Before you start stereotactic radiotherapy (SRT), your scans and medical history will be reviewed by your team of healthcare professionals. They will help and support you throughout your treatment.

They will prepare your individual treatment plan which will be based on your condition and tumour type.

SRT is for small tumours which might be difficult to remove by having surgery, or where surgery has a high risk of side effects.

Your treatment plan will be discussed with you in more detail before you start treatment. We will also discuss if there are any other treatment options that are suitable for you.

Stereotactic radiotherapy (SRT)

Radiotherapy uses high energy X-rays to treat tumours. It works by damaging the tumour cells so that they die or stop growing.

Side effects generally only affect the area where you are having treatment.

SRT is a very accurate way to give a high dose of radiation to small areas of the brain. It targets a very precise point. This allows us a better chance to control the tumour and reduces damage to surrounding healthy tissues.

It is given in small doses called fractions. The number of fractions you receive (between 1 and 5) will depend on which course of treatment is best for you.

  • When 1 fraction is given it is called stereotactic radiosurgery (SRS).
  • When more than 1 fraction is given it is called stereotactic radiotherapy (SRT).

Before radiotherapy starts


Tell us as soon as possible if you have a pacemaker as you will need to have a pacemaker check.


If you already have a ventriculoperitoneal shunt (V-P) fitted, we will need to know if it is a programmable type of shunt. If you have been given an information card please bring this with you.


If you’re able to become pregnant and have regular periods we will ask if you are pregnant.

It is very important that you are not, and do not become pregnant while you have radiotherapy planning and treatment.

If necessary, speak to your GP about types of contraception suitable for use during radiotherapy.

Tell us immediately if you think you might be pregnant at any time during your course of treatment.

The team looking after you

You will meet a range of healthcare professionals as part of your treatment and care. This includes neuro-surgeons, neuro-oncologists and neuro-radiologists. They are specialists at diagnosis and treatment of disorders of the nervous system. 

Clinical oncologists are doctors trained in the use of radiotherapy and chemotherapy. The consultant clinical oncologist will be in charge of your care.

Therapeutic radiographers are specifically trained to plan and deliver the radiotherapy. They provide support and advice on how to manage any radiotherapy side effects. The radiographers will be responsible for you while you are receiving radiotherapy.

Stereotactic radiosurgery (SRS) radiographers will provide support and advice on all aspects of your treatment.

Clinical nurse specialists (CNS) provide support and advice on how to manage any side effects of radiotherapy and chemotherapy.

Preparing for your treatment

Before your treatment you will have:

Making your mask

You will need to wear a close fitting plastic mask every time you have radiotherapy treatment. This makes sure that your head is kept still so that the treatment can be given accurately.

You will be given an appointment to have your mask made. This will be in the mould room and it usually takes about an hour to make your mask.

The mask needs to be a very snug fit. Making the mask is painless and you are able to breathe normally.

You will need to prepare, so before your appointment:

  • Have a shave and completely remove all facial hair (beards and moustaches).
  • If you are planning a haircut, this must be done before the fitting.
  • If you wear make-up or have false eye lashes you will need to remove these. They can be reapplied when you have finished your treatment.

At your appointment

You will be asked to remove your shoes and any bulky clothes.

We will help you to lie flat on your back on a treatment table. This is the position that you will be in for the CT scan and for all of your treatments.

To make your mask, a thin sheet of plastic is put in warm water to soften it. It is then put over your face and moulded to your forehead and chin. It feels like having a hot cloth on your face.

Image of moulded mask

The mask will become rigid as it dries and might get slightly tighter. This is normal and will help to keep your head still.

Your mask will be removed once it is set. You will wear your mask for your CT scan but not for your MRI scan.

CT scan

A CT scanner is a special X-ray machine that produces a series of detailed images showing the structures in your head.

You can eat and drink normally on the day of your scan and throughout your treatment appointments. There is no harm in you being around other people.

Read more about having a CT scan.

During the CT scan

You will lie on the scanning table in the same position as when you had the mask made. Your mask will be placed over your face and secured to the table.

You will be able to breathe normally with the mask on and you do not need to hold your breath.

A radiographer might need to take a photograph of you in the mask. This is only used to set up your treatment.

When you are in position, the table will be raised to go through the scanner. The radiographers will leave the room but they will be watching you at all times on closed circuit television (CCTV).

You will feel the bed slowly move in and out of the scanner and hear the machine buzzing. The scan should only take a few minutes.

After the CT scan

Once the scan is completed, the radiographers will come back into the room and remove the mask.

You will be helped down from the scanning table and you can then get dressed. You will be given instructions about your MRI scan.

MRI scan

An MRI scan is also needed to plan your treatment. You do not need to wear your mask for this scan.

Read more about having an MRI scan.

Before the MRI scan

We will use a contrast called Gadolinium, which is a fluid that shows up on MRI images, during the scan. It is used to make images clearer.

Read more about Gadolinium contrast.

Your treatment plan

Your healthcare team will review the results of your CT and MRI scans, along with your medical history. They will decide on the best treatment plan for you.

You will receive a phone call from one of the radiographers to talk to you about your treatment plan. You will be able to ask any questions.


Resource number: 4459/VER4
Published date: March 2024
Review date: March 2027

Trusted Information Creator. Patient Information Forum

Contact us

Contact us if you have any questions or concerns about your treatment. Monday to Friday 8:30am to 5:30pm

Radiotherapy reception, phone: 020 7188 7188, extension 57542 or 57569

Radiotherapy bookings, phone: 020 7188 3160

Stereotactic radiographer, phone: 020 7188 7188, extension 56769

Radiotherapy treatment support team, phone: 020 7188 4220

Acute oncology assessment unit, phone: 020 7188 3754

Out of hours
If you require assistance out of hours, phone: 020 7188 3754, to speak with an acute oncology clinical nurse specialist (CNS). Please have your hospital number ready.

If you are concerned, please go to your local emergency department (A&E). 

Do you have any comments or concerns about your care?

Contact our Patient Advice and Liaison Service (PALS)

Is this health information page useful?