Skip To The Main Content

What Happens During External Radiation Therapy for Non-Hodgkin Lymphoma

External radiation therapy is the most common type given for lymphoma. You can usually have this as an outpatient in a hospital or a clinic. That means you don't need to stay overnight in the hospital. This type of radiation may come from a machine called a linear accelerator.

Preparing for radiation treatments with simulation

To prepare for your treatment, you will have a session, called simulation, with your radiation therapist. This meeting helps determine which position you'll need to be in for your radiation treatments. Your doctor will want to make sure that the radiation is directed at the exact same spot each time. The appointment may take up to two hours. Here's what you can expect to happen during the simulation process:

  • You may have imaging scans, such as CT scans. These are scans that let your doctor see inside your body. Such tests help doctors pinpoint the exact location of the lymphoma. That way, your doctor knows exactly where to target the radiation.

  • You'll lie still on a table while a radiation therapist uses a machine to define your treatment field. That field is the exact spot on your body where the radiation will be aimed. You may have more than one treatment field if you have lymphoma in more than one place. Once you've found a comfortable position and it's clear where the radiation needs to go, the radiation therapist will mark your body with an ink dot (tattoo) that won't wash off right away in the shower.

  • If you're having total body irradiation, you may have to stand in a special machine. Or you may lie down on either your stomach or your back.

  • Depending on the area being treated, you may have special protective shields over organs such as your lungs, heart, and kidneys to protect them from high-dose radiation.

  • You may also have body molds made to help keep you from moving during the treatment.

What happens on the days you have radiation

On the days you have radiation, you may need to put on a hospital gown. Then you'll lie on a table while the machine is placed over you. The experience is much like that of getting an X-ray. You stay in the radiation room for 20 to 30 minutes, but the treatment itself could take just a few minutes. The radiation therapist lines up the machine exactly with your marked treatment fields, located during the earlier simulation.

The radiation therapist leaves the room to turn on the machine, but you will be able to talk to each other over an intercom. You may hear whirring or clicking noises. Many treatment plans require that you get radiation treatments every day for five days in a row for several weeks. You will not be radioactive during this time.

Electron beam therapy is a specific type of external radiation. Your doctor may recommend it for certain types of lymphoma that only affect the skin. It is different from standard external radiation because the beam treats the skin only and does not penetrate it or go further into the body.


MetroWest Medical Center provides advanced medicine and personalized care, right here in your community.

Click here to see our services 


The Center for Heart & Vascular Services. At the forefront of heart and vascular disease for more than 25 years.

Learn More