Stereotactic Radiosurgery is a treatment available for the following conditions:
This page has been written for patients who are considering the option of Stereotactic Radiosurgery. This is a guide and you should discuss any worries you may have with the medical team treating you. Referrals for this treatment are made through to the neurosurgery department. The treatment and the steps of care are described. A team of doctors, nurses, radiographers, and physicists are involved in the treatment with inter-related but slightly different jobs to do. The decision of whether to proceed with treatment is one you take with your neurosurgeon and/or oncologist, our Liaison Nurse is there to help you through the process.
What is stereotactic radiosurgery?
It is image guided ‘surgery’, with treatment using a fine beam of radiation rather than through a traditional invasive operation. Stereotactic surgery has been part of the work of the South West Neurosurgery Centre for many years. By applying a geometrically precise metal frame to the skull, the position of any point within the head can be calculated and in the past we have used this technique to pass needles accurately deep into the brain.
Now new technology is able to combine the use of radiation with stereotactic surgery. The combination of the principles of stereotactic surgery, the computerised manipulation of detailed brain images and the ability to modify in great detail the beam of radiation from a radiation machine are the components of stereotactic radiosurgery.
By locating the head in a frame or mask the position of any lesion can be accurately determined by the computer controls. The beam of radiation is shaped to the beam’s eye view of the target lesion; these changes to the beam can be controlled as it passes in an arc around the head. Much higher doses of radiation at the target can be used on the lesion but at the same time preserving the surrounding brain.
How does radiosurgery affect a tumour?
If the tumour is benign (such as an acoustic neuromas or meningioma) the main aim of radiosurgery is to halt the growth and prevent further problems. The treatment causes the blood vessels within the tumour to thicken and block so that the centre dies. In the first few months after the treatment the tumour can increase a little in size and then subsequently shrinks, in some cases the tumour can shrink greatly or even disappear. Because there is not a guarantee that the tumour will not continue to grow further scans are likely to be needed.
How does the radiosurgery affect an arterio-venous malformation?
An arterio-venous malformation is a knot of blood vessels that have developed abnormally. At the centre of the knot there are direct connections between the arteries and veins called the nidus. Radiosurgery is targeted on the nidus area and over many months after the treatment the blood vessels thicken and block off, stopping flow through the malformation. It can take up to two years for the treatment to fully block the malformation.
All potential candidates are discussed at a weekly STaRS MDT (Multidisciplinary Team) meeting. A team of staff are all integral to the decision whether this treatment should be offered and how it should be delivered. You will receive a letter from the MDT along with your general practitioner confirming the team’s findings. The team will be assessing the type of problem, the position, the size, and the shape. In some circumstances the team will recommend a referral to the National Centre in Sheffield the lesion is small or particularly near to a vital structure. This is a new team, starting work at the beginning of 2005 and includes:
Liaison Nurse, Tony Shute. Will coordinate the treatment admission, will be available for you to contact, help arrange overnight accommodation.
Neurosurgeon, James Palmer. Leads on the treatment of patients with acoustic neuromas and benign brain tumours. Defines the lesion to be treated and the nearby critical structures.
Neurosurgeon, Peter Whitfield. Leads on the treatment of patients with arterio-venous malformation. Defines the lesion to be treated and the nearby critical structures.
Oncologists, Steve Kelly & Sarah Pascoe. Plan and prescribes the dose of radiation required to the lesion.
Radiologist, Will Adams. Completes the scans and angiograms and helps the neurosurgeons define the lesion to be treated and the nearby critical structures.
Physicist, Ashley Richmond. Plans the treatment process, works out the angle, number and strength of radiation in each arc of treatment.
Physics Technician, Pat Kelly. Supports the physicist in the treatment process and the neurosurgeon in the use of the stereotactic frames and mask immobilisation device
Senior Radiographer, Theresa Treloar. Positions the patient on the STaRS machine and delivers the treatment prescribed
The steps of treatment
- Receive a confirmation of treatment date usually communicated by the Liaison Nurse
- First visit to Mayflower Ward, Level 3 for planning MRI scan which will usually be the day before the treatment date. If you live some distance away arrangements are made for you to stay in nearby accommodation
- Arrive on Mayflower ward by 0800 on the treatment date which will usually be a Friday
The head frame will be placed in the treatment room on Mayflower ward using local anaesthetic. The head frame is designed to restrain your head during treatment and to hold the reference markers in a fixed position in relation to your lesion. This procedure takes about 30 minutes, four injections are needed. It is a little uncomfortable putting the frame on but once in place you will be able to sit and move around comfortably.
- A CT scan is then performed with the frame in position, following which you return to Mayflower ward. If you are having treatment for an arterio-venous malformation at this stage you have an angiogram (which you will have had before at some point in your care).
There is a delay between the CT or angiogram while the final treatment plan is determined. You then are taken on a chair to the treatment centre.
- The team now completes the treatment plan and a series of carefully controlled quality checks are made to ensure that the shaped radiation beams will be guided precisely to the defined target position.
- The radiographer will position you on the treatment couch, the head frame is connected to the couch so your head will not be able to move during the procedure. Final checks are made by the neurosurgeon and physicist and then the treatment takes a 30-45 minutes to complete.
- The frame is removed and then you are ready to be discharged within 1-2 hours of the treatment.
- If you have an angiogram you will need to travel to the treatment centre on a trolley and stay overnight following the treatment.
- What is fractionated treatment?
In some situations the STaRS MDT will recommend that you have a number of treatments using smaller doses for each treatment. In this situation a head frame is not used and a mask of your face and neck is custom made. This is used for each of the treatments so that the accurate position is reproduced each time. Constructing the face mask is completely painless and typically requires no anaesthesia.
What side effects can I expect?
The procedure of treatment is not painful but the head frame positioning can be uncomfortable. Side effects you might experience immediately following treatment include headache and dizziness. Other potential side effects and risks will depend on the type of condition and will be discussed with you.
What should I expect at the treatment session?
You do not need to bring special clothing or equipment to the hospital, remove all jewellery and leave all your valuables at home. You might want to dress comfortably and bring a book or something else to keep you busy during waiting periods. You may also bring a friend or relative with you and he/she may stay with you during the day. However, during the treatment procedure, your companion will have to leave the treatment room. Please make sure to arrange transportation home as you might fell tired after the treatment; driving is not recommended.
Questions to ask the team
What are the typical stages of my illness?
What are the best treatment alternatives for me?
How long will the treatment take?
Is there anything I need to pay attention to before or after the treatment?
What are the side effects of radiotherapy?
How likely is it the tumour will continue to grow?
Is there specific statistical data available regarding my illness?
Will my PCT cover the costs of this treatment?
What can I do to accelerate my recovery?
Are there former patients, who I could talk to?
Benign - Not cancerous
Cancer - A generic term for more than 100 different diseases that are characterised by the uncontrolled abnormal growth of cells. Cancer cells usually invade and destroy normal tissue. Cancer cells can travel through the blood stream and lymphatic system to reach other parts of the body.
Chemotherapy - Treatment with toxic chemicals
Computerised Tomography (CT) - A form of x-ray imaging in which 2D sections of a patient’s anatomy are reconstructed from x-rays projecting through the body from many different angles.
Head Frame - Device which immobilises the patient’s head for the treatment procedure. The head frame is the platform which the 3D coordinates are developed.
Linac - An abbreviation for ‘linear accelerator’ a machine that creates photon x-ray energy
Magnetic resonance imaging (MRI) - A technique used to image internal structures of the body. MRI displays the tissues better than CT but are more susceptible to geometric distortion.