The first step in external beam radiotherapy is to have a special planning scan (CAT scan) of your pelvis. The information on this scan will allow your doctor (oncologist) to see exactly where your prostate is and make a map of the areas that need treatment. During the scan the doctor will place three small dots of ink on your skin. These are permanent ‘dots’ that will be used to make sure you are in exactly the same position for your treatment each day.
The doctor will then ask a radiotherapy physicist to make an individual plan for your treatment. They will use a computer programme to decide exactly where the X-rays need to be aimed to treat your prostate gland while trying to avoid as much of the normal tissue in the surrounding areas (bowel, bladder) as possible. This process is very complicated and
will take one to two weeks to be completed.
When the doctor is satisfied with your plan, you may need to go back to the radiotherapy department for one final check to position the X-ray beams before the actual treatment starts. This is known as a verification visit.
The X-rays are made in a special machine called a ‘linear accelerator’. When you go for treatment, the radiographer will ask you to lie on your back on a firm bed attached to the machine. Part of the machine will move around you and direct X-rays at your prostate from different directions.
The treatment will only take a few minutes and is completely painless. It is important that you lie very still while the treatment is being given. You may be asked to drink some water before each therapy as this will fill your bladder and reduce the amount of bladder tissue in the
You will have between 20 and 40 treatment sessions over four to eight weeks as an outpatient from Monday to Friday (not weekends). There are two types of external beam radiotherapy that are available. These use different methods to reduce the amount of radiation given to the normal tissues surrounding the prostate gland. This can reduce side effects and also allow higher doses of radiation to be concentrated on the prostate gland itself.
3D conformal radiotherapy uses special ‘blocks’ within the linear accelerator to shape the beams to fit the exact shape and size of your prostate. Intensity Modulated RadioTherapy (IMRT) is a newer type of conformal radiotherapy. It can be used to adjust the dose of radiotherapy that is given to different parts of the treatment area.
Your doctor may recommend that you take a course of hormone therapy before radiotherapy
to shrink the prostate, and maybe afterwards for some months.