External beam radiotherapy

External beam radiotherapy (EBRT) (also known as teletherapy) is a form of ionizing radiation therapy delivered by a medical linear accelerator (or historically a cobalt-60 source) to a patient lying on a treatment bed. Megavoltage x-rays (4-25 MV) are the most commonly used. Alternative forms of EBRT include electron therapy, orthovoltage x-rays (0.1-1 MV) and particle therapy (proton therapy, neutron therapy and carbon ion therapy).

There are many types of external beam radiotherapy ^1-5:

• conventional (2D) radiation therapy
• 3D conformal radiation therapy
• intensity-modulated radiation therapy (IMRT)
  • rotational/helical/arc IMRT
• stereotactic radiosurgery
• particle therapy: most commonly proton therapy