Types of external radiotherapy

Conformal radiotherapy is also called three-dimensional (3D) conformal radiotherapy. Conformal radiotherapy uses a device inside the linear accelerator that can be adjusted to match the shape of your tumour. The radiation beams are precisely focused so that nearby healthy tissue is spared. This results in fewer side-effects, allowing a higher dose of radiation to be given.

Uses smaller, more precise radiation beams than standard radiotherapy. The beams are targeted at your tumour from several angles for a very accurate, high dose of radiation.

Generally used on small tumours that are not suitable for surgery, such as brain or lung tumours. Stereotactic radiosurgery is like stereotactic radiotherapy, except that it is given in just one dose. It is used to treat tumours in your head (intracranial radiotherapy).

Read more about Stereotactic radiotherapy and stereotactic radiosurgery.

DIBH is used when radiotherapy is given to the chest area. The idea is that you take deep breaths and hold them for short periods while the radiation is delivered, to shift your heart and other structures away from the beam of radiation. For example, when giving radiotherapy to the left breast, which is near the heart. When you stop holding your breath, the radiation beam is switched off. Your radiation therapist will help you during your DIBH treatment so that you know how to breathe the right way.

Intensity-modulated radiotherapy (IMRT) can shape the radiotherapy beams so that different doses of radiotherapy can be given to different parts of the treatment area.

IMRT also helps to reduce doses of radiation to normal, healthy tissues compared to standard radiotherapy.

Volumetric-modulated arc therapy (VMAT) is a form of IMRT that allows for even more efficient and accurate use of intensity-modulated radiotherapy. It is not suitable for everyone and it is not as widely available as IMRT.

Often tumours can move between and during radiotherapy. For example, when you breathe, swallow or fill your bladder. Image-guided radiotherapy (IGRT) allows for changes in your tumour’s location. Images are taken of your body every time you have treatment. These images help your therapists to adjust your radiotherapy so that it is targeting the tumour. By constantly checking the size and location of your tumour, your doctors can make sure that your treatment is as accurate as possible.

For some types of leukaemia, lymphoma or myeloma, doctors may use radiotherapy to the whole body. This is called total body irradiation. This is part of the preparation for a bone marrow transplant or a stem cell transplant. The radiation kills off all bone marrow, including cancer cells, before healthy bone marrow is given back to you. Read more about total body irradiation.

Contact radiotherapy can be used to treat cancers on the surface of your skin. This includes basal cell carcinomas (BCCs), squamous cell carcinomas (SCCs) and other skin conditions. It uses energies much lower than those of the linear accelerators. Sometimes it is used to treat secondary cancer in the bone, for example in the ribs. Different sizes of applicators can be used, depending on the size of the treated area. The applicator is put into the head of the machine and then placed on the skin surface. This is why it is called contact radiotherapy.