By using computers and images of the patient (X-ray images, Computed Tomography (CT) images, Magnetic Resonance (MR) images, Positron Emission Tomography (PET) images) physicians, physicists and dosimetrists can determine the optimal way to deliver the prescribed dose of radiation to the tumor, while minimizing the dose to normal, critical structures.

EBRT can be used in conjunction with surgery, chemotherapy, brachytherapy and a variety of other weapons used to battle cancer.

Various techniques can be used to deliver the radiation beams produced by the linear accelerator to the patient. These include 3-D conformal radiation therapy and Intensity Modulated Radiation Therapy (IMRT).

3-D EBRT uses multiple beams of radiation that are specifically shaped to correspond to the projection of the tumor in each beam. This reduces the amount of normal tissue irradiated by the beams.

IMRT allows the modulation (increases or decreases) of dose within the tumor and allows the physicians, physicists and dosimetrists to specify dose limits to critical organs and other normal tissue.

Daily treatment sessions using EBRT usually only last 10 to 15 minutes, this includes both set-up (patient positioning) and treatment times. Treatments are usually given 5 days a week and last from 4 to 8 weeks.