Stereotactic Radiosurgery

Stereotactic Radiosurgery

This information is of a general nature only. Please consult your doctor for specific advice concerning your condition.

What is stereotactic radiosurgery?

Radiosurgery is the use of sophisticated technology to identify a target (usually a brain tumour) and apply a 3 dimensional dose of radiation precisely to that target (within an accuracy of around 1 mm). It is an alternative to standard open surgery in some patients.

Radiosurgery involves collaborative planning by the neurosurgeon and radiation oncologist to design a treatment that will be accurately shaped to the tumour with a rapid fall off of dose nearby so that other critical structures are spared.radiosurgery.jpg

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If the treatment uses radiation, and not a scalpel, why it is called radiosurgery?

There are 3 reasons why it is called radiosurgery.

Firstly, there is an emphasis on exactly targeting a tumour and avoiding injury to any surrounding structures, similar to traditional open surgery.

Secondly, radiosurgery is usually a single dose, 1 off treatment- again, similar to surgery.

The third reason is historical. Radiosurgery originated from a neurosurgeon, who conceived of a method of doing neurosurgery where the X-ray replaced the scalpel as a form of knife.

Do patients always have their treatment in a single session?

There is an alternative to radiosurgery called fractionated stereotactic radiotherapy. It differs only in that the same precise technology delivers the treatment to the tumour using smaller individual doses over multiple days.

Why would a patient have their tumour treated over multiple days, when it might be more appealing to get it over and done with in a single session?

Certain tumours have important nerves intimately associated with them- or even within the tumour. In these cases it may not be desirable to give the high single dose of radiation to the tumour since a portion of the nerve may receive the high dose intended for the tumour, with potential for complications. This can be particularly relevant for tumours around the hearing (cochlear) nerve and seeing (optic) nerve.

Do patients require an anaesthetic or admission to hospital?

No, patients receive their treatment whilst awake- and can return home the same day.

Is there any pain?

No- the X-rays are undetectable, you can’t see, hear or feel them!

What complications can occur?

This is always best discussed in the context of your individual condition.

Can you lose hair with this treatment?

Occasionally patients will lose a very small amount of hair, but most patients don’t lose any hair.

I have heard about frameless radiosurgery, what is this?

Traditionally radiosurgery has required the application of a head frame- with 4 pins bolted into the skull in order to achieve the precise positioning of the patient (and their tumour) for their treatment.

Some of the modern radiosurgery devices have methods of achieving the same or similar accuracy in positioning the patient using image guidance systems on the radiosurgery machine. A mask is used in these patients, though it is the image guidance system and not the mask itself that ensures accuracy down to the last millimeter.

So is frameless radiosurgery mainly about patient comfort?

Comfort is one issue, but there are two other issues to consider.

Firstly, if the patient might benefit from having multiple smaller dose treatments (fractionated stereotactic radiotherapy), then the traditional head frame with pins in the skull cannot be used, but frameless treatment is suitable.

Secondly, other areas in the body that cannot have a rigid frame screwed into them (for example spinal tumours) can be treated using frameless radiosurgery, since the contour of the bones is used for the precise patient positioning.

What are the common names of radiosurgery systems?

Names such as Cyberknife, Gamma Knife and Novalis refer to systems specifically developed for radiosurgery use, but other units use Varian or other equipment.
RS127_NovalisTx_1.jpg Novalis TX at Royal Prince Alfred Hospital, New South Wales.

Do the systems vary in how accurately they can treat the tumour?

The short answer is no. In the case of secondary tumours to the brain, multiple types of systems were used in one of the large trials published in the prestigious medical journal, The Lancet. Patient outcomes did not vary based on which type of machine was used. This would be expected since at a technical level the capabilities are very similar.

We are talking here about single dose radiosurgery, since not all of the systems have the potential for the multiple dose treatment.

What types of tumours are suitable for treatment?

The most commonly treated tumours are secondary brain tumours (also known as metastases or mets), acoustic neuromas, meningiomas, and pituitary adenomas. There are a couple of non-tumour conditions which are also commonly treated called arteriovenous malformations (AVMs) and trigeminal neuralgia.

Other less common (or more controversial) indications for treatment include gliomas, craniopharyngioma, glomus tumours, cavernous malformations, chordomas and chondrosarcomas and epilepsy.

Radiosurgery is not suitable for all patients, so it is best to visit a team that has both neurosurgery and radiation oncology expertise.

Information for Patients Undergoing Radiosurgery

This information is of a general nature only. Any specific information provided by your doctor should be adhered to if it differs from the information below.

All stereotactic radiosurgery procedures are performed under the care of Dr Jonker and a radiation oncologist (usually Dr Patanjali) at Sydney Radiosurgery, Royal Prince Alfred Hospital.

You will need to have an appointment to see the radiation oncologist and sometimes this can be done on the same day that you have your planning appointment.

If you are having a single dose treatment you will have two appointments with the radiation therapists who deliver the treatment (and they will contact you to advise you of the time).

On the first appointment a mask will be made and a CT scan performed. Often an MRI will also be performed on this day.

You will then go home and a second appointment will happen anywhere from a few days to a few weeks later in which you actually receive the stereotactic radiosurgery treatment. You will be advised of details of your booking by the radiation therapists.

If you are booked for a multiple dose treatment (fractionated stereotactic radiotherapy) this will then be the first of a series of appointments that may run for 5-6 weeks, each day (excluding weekends).

There are no restrictions on you on the day of treatment. Typical treatment times are 30-45 minutes for a single dose treatment, but can sometimes be longer. You may drive home. Usually, no special medications are required.

It is common to feel a mild headache or some fatigue for a few days afterward.

Follow-up will initially be 4 weeks after your treatment, with the radiation oncologist. Further follow-up appointments will then be made depending on your diagnosis, and you can have these at the Stereotactic Radiosurgery Clinic at Royal Prince Alfred or with Dr Jonker at the BMRI.

 

Surgery Information