Radiotherapy
A machine outside the body aims radiation from several directions at a set area. The aim is to damage the DNA of cancer cells, with as little radiation as possible reaching healthy tissue nearby.
How does radiotherapy work?
Radiation damages the DNA of cells. A cancer cell whose DNA is damaged beyond repair stops dividing or dies, and the body clears it away. This does not happen at once. Damage builds up over days and weeks of treatment, and cells keep dying for weeks or months after treatment ends.
Radiotherapy is a local treatment. It treats only the area that receives the radiation, not the whole body.
What is the aim of treatment?
The aim is not the same for everyone. Before you start, ask what yours is.
- To remove the disease or stop it coming back
- To shrink a tumour before surgery or chemotherapy
- To destroy cells left behind after surgery or chemotherapy
- To ease pain and problems such as breathlessness, sometimes with a single session
Radiotherapy is sometimes the only treatment, but it more often comes alongside surgery, chemotherapy or other medicines.
Why several angles?
The machine aims radiation at the target from different directions. These angles and the shape of the beam are worked out beforehand on CT images, with the help of a computer. In methods such as IMRT the beams are smaller and their strength can be adjusted. In IGRT, images are taken during treatment to check your position and the target. Which method suits you depends on the type and location of the tumour.
How is it given?
- Planning CT: Images are taken in the position you will be treated in. Small dots may be placed on your skin, and a mask is made for the head and neck.
- Treatment planning: The doctor sets the treatment area and the dose, and the beam paths are calculated.
- Sessions: Most patients are treated once a day on working days. The radiation lasts about 1 to 5 minutes, and a whole session usually takes 30 to 60 minutes.
The total number of sessions depends on the type of cancer, the aim of treatment and the dose.
What side effects can it have?
Radiation also affects healthy cells near the tumour. Side effects depend mostly on the area treated. Tiredness and skin changes are common in every area, and hair falls out only in the area treated.
Healthy cells usually recover within a few months of finishing treatment. Some effects stay, and some appear months or years later. The side effects of each area are listed in the patient guide.
Internal radiotherapy
In brachytherapy, the radiation source is placed inside or near the tumour. In another type, a radioactive substance is swallowed or injected and reaches cells through the blood. This page is mostly about external radiotherapy, and the safety rules for these two types differ.
Frequently asked questions
Will I feel the radiation?
No. You cannot see it, and it has no sound, smell or feeling. You only hear the machine moving.
What if I feel unwell during a session?
Tell the therapist. They watch you through a window or camera, can hear you, and can stop the machine at any moment.
Can the same area be treated again?
Each area of the body can safely receive only a certain amount of radiation over a lifetime. If the disease returns, the decision depends on the type of cancer, its location and the earlier radiation. That is why you should keep a record of past radiotherapy.
The first step, a review of your records.
Go to the booking page or talk to support. Have your pathology report and scans ready.