There are different forms of Radiotherapy which can be prescribed to cancer tumours, certain non-cancerous growths and even in other special circumstances to treat some chronic diseases and abnormal scar tissue.  This takes place in special radiotherapy units, in hospital surgical theatres and in specialised Nuclear medicine suites. The accuracy of this treatment has increased exponentially over the last few decades and we are priviledged to have access to world class equipment and technologists, radiotherapists, physicists, physicians and specialised pharmacies.

External radiation or external beam radiation is the most common type of radiation therapy used for cancer treatment. A machine called a linear accelerator or Linac is used to aim high-energy rays or beams from outside the body into the tumour.

Radiation technology allows the very careful delivery of external beam radiation therapy. The machine focusses the radiation on the exact location where it needs to be so that the normal tissues are affected as little as possible.

Most people get external beam radiation therapy over many weeks. Usually, they visit the treatment centre every weekday (Monday through Friday) for a certain number of weeks.  But some people may need to only receive radiation over one day.  Your Oncologist with your assistance and tumour type will decide how much radiation is needed to treat your cancer and how often you need to get it.

Three-dimensional conformal radiation therapy (3CD-CRT) is a type of external beam radiotherapy. The Linac delivers radiation beams from outside the body.  The beams are delivered from different directions designed to match the shape of the tumour.  This helps to reduce radiation damage to normal tissues and better kill the cancer by focusing the radiation dose on the tumour’s exact shape and size.

Intensity-modulated radiation therapy (IMRT) is a 3D-CRT, but the radiation beam is made up of multiple smaller beams.  Some tumours wrap around sensitive structures – for example, the spinal cord – and treating the tumour without damaging normal body tissues can be very difficult.  This technique allows the radiation therapy to be mapped and delivered more precisely.

Volumetric modulated arc therapy (VMAT) is like IMRT.  This technique delivers the radiation dose continuously as the Linac rotates in an arc and so the treatment is delivered slightly faster than IMRT.

Stereotactic radiosurgery (SRS) is a highly precise form of radiation therapy and delivers a very high dose of radiation over 1-5 treatment sessions but can be longer at the Oncologist’s discretion.  It is useful when the tumour is small but cannot be removed surgically because of its location. This technique is specific for tumours that are growing in the brain.

Stereotactic body radiation therapy (SBRT) is a highly precise form of radiation therapy and delivers a very high dose of radiation over a few treatment sessions (usually less than 5).  SBRT is useful when the tumour cannot be removed surgically due to its location or for people who are not able to have surgery due to other medical conditions.  This technique is like SRS but it is used for tumours that are growing outside of the brain. Common disease sites include the liver, lungs, abdomen, and spine.

Orthovoltage is a type of radiation therapy that has been available since the turn of the 20^th century. The x-rays used in this treatment are strong enough to kill cancer cells but do not penetrate more than a few centimetres beyond the surface of the skin.  This makes it an effective treatment for superficial, small tumours, such as skin cancers and non-malignant skin conditions including keloids.

VMAT is different to normal IMRT in that the radiotherapy machine rotates around the patient during a radiotherapy beam in an arc shape. It is very accurate, shortens the treatment time, and uses a lower overall dose of radiation.