External Beam Radiation Therapy In external beam radiation
therapy , radiation is produced by a machine called a linear
accelerator. Short bursts of x-rays are fired from the machine
at your cancer. The x-rays come out in square shapes. The
radiation oncologist designs special blocks to shape the
radiation beam so that it treats the cancer and as little normal
tissue as possible. Your radiation oncologist may also use some
of the newer techniques, such as intensity modulated therapy
(IMRT) and conformal treatment planning, to further localize and
restrict the delivery of radiation to your tumor. Like
chemotherapy , the side effects from radiation result from
injury to the normal tissues. There are many new ways that the
radiation oncologist can customize your treatment to try to kill
as much cancer while sparing as much normal tissue as possible.
The radiation oncologist will determine how many treatments you
will receive; sometimes they will be once a day and sometimes
twice per day. Each treatment generally