What is Radiation Therapy?


Radiation therapy beams radiation from a machine to destroy cancer cells. The radiation damages DNA in the cancer cells and causes them to die.

A machine that delivers radiation therapy is called a Linear Accelerator, and can look a lot like an X-ray machine. It will not touch you and the radiation therapy itself is usually painless. However, you may have discomfort or pain in the treated area later on. This, along with other possible side effects, will be discussed with you before starting treatment.

Patients are always given the lowest possible dose of radiation appropriate to their treatment plan. This helps limit side effects and avoid damaging the surrounding healthy tissue. These side effects can be further minimised with advanced radiation oncology techniques and technologies like those used at ARO.

To download the Cancer Society information booklet on Radiation Therapy click here

In more detail

There are a few different types of radiation; the most common are photon beams, which are created by linear accelerator machines (LINAC) using electricity. Other types of radiation include X-ray beams, cobalt irradiation and particle beams.

Radiation therapy targets DNA, which is the genetic code controlling the cell’s behaviour. The radiation works by damaging the DNA or by creating charged particles, called free radicals, which also damage DNA. The cancer cells stop growing or die and then the body breaks them down and gets rid of the waste. In order for the treatment to be most effective, the radiation field will cover the whole cancer and a small area around it. If healthy cells are damaged they are usually able to repair themselves over time. 

There are two types of radiation therapy: radical or curative and palliative radiation therapy.

Radical or curative radiation therapy is treatment designed to put cancer into remission. Treatment is divided into small doses, or sessions, called fractions. This allows time for healthy cells to recover between sessions. The treatment team will use a range of scans, such as CT, PET-CT or MRI scans, to tailor a specific treatment and monitoring plan.

Palliative radiation therapy is treatment to relieve pain and other cancer symptoms. Often treatment is just one dose. Because palliative care aims to limit or reduce cancer cells, a lower dose is required. This means side effects are fewer and not as severe as those that can occur with curative treatments.