External Beam Radiotherapy

Radiation Oncology Victoria patient treatment

External beam radiotherapy is the most widely used type of radiotherapy. It uses a machine called a Linear Accelerator (Linac) to produce high-energy X-rays which are directed at the tumour.

The following steps are similar for both Intensity Modulated Radiotherapy (IMRT) and Volumetric Modulated Arc Radiotherapy (VMAT).

Step 1: Initial consultation
Before you proceed for treatment your radiation oncologist will explain the radiotherapy process to you and answer any questions you may have. Discussion will also take place with regards to treatment options and any potential short or long term side effects. An examination may be required at this appointment, along with review of any relevant X-rays, scan and test results, so please bring them along. Your next appointment will be for a simulation CT scan, which may, or may not be on the same day.

Step 2: Treatment setup and immobilisation
An essential component to the external beam radiotherapy treatment is the set-up and the use of immobilisation equipment. The equipment used to position you for your simulation CT scan will be replicated each day for treatment and the equipment used is dependent on the area being treated.

The treatment set-up approach and equipment used stabilise the treatment area so that the treatment delivery can be as accurate as possible, whilst maintaining as far as possible a level of comfort. It is also often necessary for the skin in the area needing treatment to be visible so you may be asked to change into a gown.

Step 3: Simulation CT scan
This CT simulation scanning procedure, whilst similar to other scans you may have had, is specifically setup to record all the necessary images, body shape and position details needed to ensure that daily treatments can be delivered accurately to the same area on repeat occasions throughout your treatment course.

The CT scan will be performed, under the supervision of the attending radiation therapists. At its completion all required details and measurements relating to your position will be recorded and stored on file.

In most cases tiny reference tattoo dots are also placed on the skin for reproducibility of your treatment setup. These are not noticeable on casual observations and will only be completed with your notified consent. In the instance where a tattoo is not suitable (i.e. face and neck), the use of immobilisation masks or physical landmark references will be employed.

Step 4: Treatment planning
This step is performed without the patient present. The information gained from the CT scan in step 3 is used by your radiation oncologist with the assistance of radiation therapists to develop an accurate and customised treatment plan. Every plan is unique and tailored to the specific requirements of each patient. Once the treatment plan has been completed, approved by your radiation oncologist and had all required checks completed, your treatment is ready to commence.

Step 5: External beam radiotherapy treatment
You will be positioned on the treatment couch in the same position as you were for the simulation CT scan. Each session will usually take between 10–20 minutes, this includes radiation therapists positioning you on the treatment couch and for the radiation dose to be delivered.

Please note the first treatment may take slightly longer due to quality assurance and procedure verification processes.

The radiation therapists will leave the room and monitor you closely on closed circuit TV and audio intercom. During your treatment the radiation therapists will move both the treatment machine and couch to precise required positions. The machine will make a noise during treatment that is like a buzzing, whirring sound.

The treatment itself is PAINLESS, just like having an X-ray taken.

Most treatments take place daily (Monday to Friday) over a period of 5-8 weeks.

We encourage you to bring along a family member or a friend. They may be present in the treatment room upon request but must leave when any of the machines are switched on.

Step 6: After Treatment
Routinely (usually weekly), after your treatment sessions you will be reviewed by your radiation oncologist. This is to check your progression through the treatment and to discuss any questions or concerns you may have. Other appointments after treatment may also occur for reviews and discussion with the department nurse or other allied health professionals (such as dieticians, physiotherapists, etc).

Step 7: Follow up consultation
An appointment will be made for you to see your radiation oncologist at the completion of your treatment. The effectiveness of your external beam radiotherapy treatment will be evaluated over time.

The radiation treatment is designed to stop the growth of tumours and therefore it may take weeks to months before the full benefit of the treatment may be assessable. Often imaging and diagnostic tests are required prior to this appointment, you will be provided with details if these are necessary.

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