A Guide to Stereotactic Radiotherapy
Note: There are two forms of stereotactic radiotherapy. There is stereotactic surgery and stereotactic radiotherapy. For information on steresotactic radiosurgery, please see stereotactic radiosurgery.
Radiotherapy (fractioned) - What does it mean?
is very precise delivery of radiation to a small area of the brain with sparing
of the surrounding normal brain. Fractionation means that the treatment course
is divided into multiple smaller doses or fractions given daily (Monday ~
Friday) over several weeks. This minimizes the effect of the radiation on the
normal brain and reduces the risk of late side effects.
To achieve high precision and to ensure that the treatment position is reproduced accurately each time, you will need to have a special frame made. The majority of patients find the head frame reasonably comfortable to wear during treatment sessions.
head frame serves three main purposes:
enables accurate reproducibility of the treatment position for each planning and
prevents movement of your head during the treatment
removes the need for ink marks on your head or face.
Prior to the treatment starting there are usually three planning visits needed. This leaflet aims to give a brief description of the planning and treatment process.
First visit – Making Your Frame
At this appointment the frame attachments will be made
specifically for you. The frame is fitted and held securely on your head in two
bite ~ a denture plate that fits onto your upper teeth.
plate ~ a moulded support of the back of your head.
Once a correct size denture plate has been chosen for you it will be filled with the soft impression material. The denture plate is then placed into your mouth and you will be asked to bite on it to form a clear impression. The material sets in your mouth but will not stick to your teeth. The material takes about 4 minutes to set. Once it has set the plate will be removed from your mouth and attached to the main frame.
Making the back plate:
A putty-like material is placed on the back plate that is also attached to the main frame. The frame is placed over your head and the mouth bite fitted onto your teeth. The back plate is then rested against the back of your head and held securely in place for a few minutes until it has set.
The frame is then secured into place by straps across your head.The frame and the dental plate do not cover the mouth, nose or face and breathing is not impeded. Once the frame has been made and is fitting well we do some measurements to ensure that the frame can be relocated in the same position at each visit. To do this we use a clear plastic helmet, called a depth helmet, and a measuring probe. These measurements are taken with you lying down so that you are in the same position as you will be for your treatment. Two or more sets of measurements will be done on your first visit. Further sets of measurements will be taken before any planning or treatment. To make the frame and take the initial measurements takes approximately one hour.
Second visit – Scanning and Planning
this appointment a CT scan will be taken of you positioned in the head frame.
During the scan you may be given an injection of contrast: this is a dye that
helps to highlight the area needing treatment. The appointment usually lasts
about 30 minutes.
The Oncologist will use the information from this scan to plan your radiotherapy and this process normally takes a couple of weeks.
purpose of this visit is to check that your treatment plan is correct. This
process is called verification and is carried out on a x-ray machine called a
simulator. A set of x-rays will be taken of you positioned in the head frame.
This appointment normally lasts about an hour.
treatment is given in one of the radiotherapy treatment rooms. At each treatment
the head frame will be fitted and measurements taken to ensure that it has been
located correctly. You will be positioned for treatment using the room lasers
the machine is switched on the radiographers will leave the room but will be
watching you on closed circuit TV. They can stop the treatment at any time. You
will not feel anything during treatment but may be aware of a buzzing sound. The
treatment is divided into several fields with the treatment machine positioned
slightly differently for each. Each treatment field takes about one minute and
the radiographers will come into the treatment room between fields. The whole
treatment takes about 20 minutes to deliver. Each week throughout
the course of your treatment you will have an opportunity to see either the
doctor or a specialist radiographer to discuss any queries or problems that
arise. The radiotherapy will not make you ill and you will be well enough
to travel. Many patients carry on their normal daily activities before and after
the daily treatment session.
You may or may not be allowed to drive yourself. This should be discussed with your doctor prior to treatment.
If you are currently taking steroids, the dose is often kept at the same level between leaving hospital after your operation and starting radiotherapy. This dose may be adjusted during your radiotherapy following discussion with the doctor.
Any side effects vary from person to person. The type and site of your tumour may also determine the side effects you may experience. The most common side effects are listed below: Unfortunately, you
The skin in the treatment area may gradually redden from the second week of
treatment onwards. It may become dry, itchy and sore especially around the ears
if they are in the treatment area. To minimise dryness and irritation aqueous
lotion may be used in the treatment area. During the summer months the area
should be protected from the sun to prevent sun damage. Any reaction will soon
clear up after treatment has finished.
This side effect varies
greatly from person to person. Generally it increases throughout the
radiotherapy and may last for a few weeks after completion of your treatment
(see information on coping with fatigue).
Further general information Your doctors and specialist nurses are in an ideal position to give you relevant information on your disease and treatment as they know your individual circumstances. Cancerbackup has a help line (0808 800 1234) and a prize winning video available in English, Italian, Urdu, Bengali, Gujarati & Hindi explaining Radiotherapy & Chemotherapy. Cancernet.co.uk has over 500 pages describing cancer, its management, practical tips and tool which patients, their carers and their doctors have found helpful during the cancer journey.