External Beam Radiation Therapy (EBRT)

What is external beam radiation therapy?
Radiation occurs when there is a release of energy caused by an electromagnetic wave or a moving sub-atomic particle. Radiation can be ionising or non-ionising.

Ionising radiation has high energy and causes the ionisation of molecules whereby a molecule gains a negative or positive charge. If this happens in human tissue, DNA damage is the end result.

What is external beam radiotherapy (EBRT)?

Ionising radiation is produced by a machine known as a linear accelerator (LINAC) and is delivered to a focused area, in the form of external beam radiotherapy.

The ionising radiation released destroys cancer cells by causing DNA damage. DNA damage will prevent the cancer cell from dividing successfully and will subsequently cause cancer cell death.

EBRT is planned and administered by a team of experienced healthcare specialists. The oncologist will explain the dose of radiation a patient requires, as well as the treatment schedule best suited to the patient's particular circumstances. EBRT is typically administered in several sessions over a period of time.

Before the therapy begins, each patient undergoes a radiotherapy planning CT scan. This is needed in order to define the exact area of treatment, so that the radiation can be delivered precisely. It is also needed to carefully plan a patient's radiotherapy in order to limit treatment related side effects.

There are a number of different forms of EBRT offered a DMO namely:

• Three-dimensional conformal radiation therapy (3D-CRT)
• Volumetric modulated arc therapy (VMAT)
• Stereotactic Radiosurgery (SRS)

EBRT side effects

Radiotherapy is painless.

However, after a few sessions of therapy, patients do start experiencing treatment related side effects. In a small percentage of patients, side effects are experienced weeks to months following radiotherapy.

A patient's side effect profile will depend on the area being treated, the duration of treatment as well as the form of EBRT used for treatment. The oncologist explains the potential side effects to each patient prior to starting radiotherapy as well as what can be done in order to limit treatment related side effects. Each patient is seen on a weekly basis by their oncologist and monitored carefully during their treatment. Rest assured, should treatment related side effects occur, the oncologist will manage the side effect accordingly.