About External Beam Radiation Therapy

What is Exter­nal Beam Radi­a­tion Therapy?

Exter­nal beam radi­a­tion ther­a­py, the most wide­ly used type of radi­a­tion ther­a­py, comes from a machine (lin­ear accel­er­a­tor) that aims radi­a­tion at the spe­cif­ic spot that is affect­ed with can­cer. The machine is large and may be noisy. It does not touch you, but rotates around you, send­ing radi­a­tion to your body from many directions.

Exter­nal beam radi­a­tion ther­a­py is a local treat­ment, mean­ing that the radi­a­tion is aimed only at a spe­cif­ic part of your body. For exam­ple, if you have lung can­cer, you will get radi­a­tion to your chest only and not the rest of your body. Exter­nal beam can also treat large areas of the body as well as treat more than one area such as the main tumor and near­by lymph nodes.

How often will I get exter­nal beam radi­a­tion therapy?

Most peo­ple get exter­nal beam radi­a­tion ther­a­py once a day, 5 days a week, Mon­day through Fri­day. Treat­ment lasts from 2 to 8 weeks, depend­ing on the type of can­cer you have and the goal of your treat­ment. The time between your first and last radi­a­tion ther­a­py ses­sions is called a course of treatment.

What hap­pens before my first exter­nal beam radi­a­tion treatment?

The plan­ning process for exter­nal beam radi­a­tion ther­a­py has many steps and may take sev­er­al days to com­plete. Dur­ing the plan­ning process, you will have a phys­i­cal exam, talk about your med­ical his­to­ry, and like­ly have imag­ing tests. Your doc­tor or nurse will dis­cuss exter­nal beam radi­a­tion ther­a­py, its ben­e­fits and side effects, and ways you can care for your­self dur­ing and after treat­ment. You can then choose whether to have exter­nal beam radi­a­tion ther­a­py.

If you agree to have exter­nal beam radi­a­tion ther­a­py, you will be sched­uled for a treat­ment plan­ning ses­sion called a sim­u­la­tion. At this time:

• A radi­a­tion oncol­o­gist and radi­a­tion ther­a­pist will define your treat­ment area (also called a treat­ment port or treat­ment field). This refers to the places in your body that will receive radi­a­tion. You will be asked to lie very still while X‑rays or scans are tak­en to define the treat­ment area.
• The radi­a­tion ther­a­pist will then put small marks (tat­toos or dots of col­ored ink) on your skin to mark the treat­ment area. You will need these marks through­out the course of radi­a­tion ther­a­py. The radi­a­tion ther­a­pist will use them each day to make sure you are in the cor­rect posi­tion. Tat­toos are about the size of a freck­le and will remain on your skin for the rest of your life. Ink mark­ings will fade over time. Be care­ful not to remove them and make sure to tell the radi­a­tion ther­a­pist if they fade or lose color.
• You may need a body mold. This is a plas­tic or plas­ter form that helps keep you from mov­ing dur­ing treat­ment. It also helps make sure that you are in the exact same posi­tion each day of treatment.
• If you are get­ting radi­a­tion to the head, you may need a mask. The mask has air holes, and holes can be cut for your eyes, nose, and mouth. It attach­es to the table where you will lie to receive your treat­ments. The mask helps keep your head from mov­ing so that you are in the exact same posi­tion for each treatment.

What are the ben­e­fits and risks of exter­nal beam radi­a­tion therapy?

Exter­nal radi­a­tion ther­a­py is an out­pa­tient pro­ce­dure. Com­pared to oth­er, more inva­sive tech­niques, exter­nal radi­a­tion treat­ment ses­sions are:

• Short
• Pain­less
• Low-risk

Exter­nal radi­a­tion treat­ment may require an invest­ment of time — a course can involve dai­ly ses­sions over sev­er­al weeks. Com­mon side effects of exter­nal beam radi­a­tion ther­a­py are depen­dent on the treat­ment site and will be dis­cussed with each indi­vid­ual patient.

To speak to a nurse nav­i­ga­tor to deter­mine if exter­nal beam radi­a­tion ther­a­py is right for you please call 1 – 855-4DMG-ONC (855−436−4662).