Total Body Irradiation (TBI): How It Works, What to Expect, and Side Effects
Updated: 6 days ago
Written and medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026 · How we review
Quick Answer: What is total body irradiation?
Total body irradiation (TBI) is a type of radiation therapy that gives small doses of radiation to the entire body to prepare for a bone marrow or stem cell transplant. It destroys cancer cells in hard-to-reach areas, makes room in the bone marrow, and lowers the chance of transplant rejection. Sessions are painless and last up to 60 minutes. [1]
What the research says
TBI improved survival in children with high-risk leukemia. In a randomized trial of 417 children and young people with acute lymphoblastic leukemia, 91% of those conditioned with TBI were alive at 2 years, compared with 75% after chemotherapy-only conditioning. Relapse was 12% vs 33%, and treatment-related deaths were 2% vs 9%. (Peters et al., Journal of Clinical Oncology, 2021) [3]
Pooled studies point the same way. A meta-analysis of 8 studies found TBI-based conditioning lowered relapse risk by 18% (6 studies, 5,091 patients) and the risk of death by 24% (7 studies, 4,727 patients) compared with chemotherapy alone, with no rise in non-relapse deaths. Severe acute graft-versus-host disease was somewhat more common with TBI. (Khimani et al., Transplantation and Cellular Therapy, 2021) [4]
Late side effects are the main trade-off. A pediatric review of 8 studies on effectiveness and 6 on late effects found late complications were significantly more common after TBI, while overall survival was similar to non-TBI regimens and disease-free survival favored TBI. (Ansari et al., Leukemia Research, 2023) [5]
Key takeaways
Total body irradiation prepares your body for a bone marrow or stem cell transplant. [1]
Treatment starts with a planning visit, then sessions up to two or three times a day for three to five days. [1]
The treatment itself is painless. You cannot feel the beams, and the machine never touches you. [1]
Short-term side effects are common. Long-term effects such as cataracts, infertility and an underactive thyroid are common, so ask about fertility preservation before treatment. [1]
Call your care team right away for fever, chills, blisters or peeling skin. [1]
How is total body irradiation different from other radiation therapy?
Total body irradiation spreads small doses of radiation across your whole body, while most other radiation therapy aims larger doses at one specific area. [1] Because the dose is lower and newer techniques limit the effect on healthy tissue, TBI is designed to treat the whole body without focusing heavy radiation on one spot. [1]
Feature | Total body irradiation | Other radiation therapy |
Area treated | Entire body | A specific part of the body |
Dose per area | Small doses | Larger doses |
Main purpose | Prepare for a bone marrow or stem cell transplant | Destroy or shrink a tumor in one area |
Usually combined with | Chemotherapy or targeted therapy | Varies by cancer |
Exact doses, scheduling and technique differ from one treatment center to another. [2]
Why is total body irradiation used before a transplant?
Total body irradiation is used before a bone marrow or stem cell transplant to clear out cancer cells, make space in the marrow, and calm the immune system so the new cells are more likely to take hold. [1]
Goal of TBI | What it does for you |
Destroy hidden cancer cells | Reaches cancer cells in the bone marrow, nervous system and other areas that are hard to treat |
Make room for new cells | Reduces your bone marrow to create space for the transplant |
Suppress the immune system | Lowers the chance your body rejects the transplant |
Which conditions is total body irradiation used for?
Total body irradiation is used, together with treatments like chemotherapy or targeted therapy, for blood and bone marrow cancers that may need a transplant. [1] These include:
Leukemia, such as acute lymphocytic leukemia and acute myeloid leukemia
Multiple myeloma
Myelodysplastic syndrome (myelodysplasia)
How do you prepare for total body irradiation?
Preparation for total body irradiation starts with a planning appointment called a simulation, which works like a trial run of your treatment. [1] It helps your care team position you so you receive the right dose.
During the simulation:
You have a CT scan to map the treatment area.
Your radiation therapist takes body measurements.
Small skin markings and photos record your exact position for every session.
The skin marks may be permanent, but they are tiny. [1]
What happens during a total body irradiation session?
A total body irradiation session places you in your planned position while a machine called a linear accelerator moves around you to deliver radiation. [1] You may stay in the hospital for several days during treatment. [1]
Here is what to expect:
Positioning. Your therapist sets you up exactly as in your planning visit.
Shielding. Boards or devices may be placed over areas such as your lungs to lower the dose there. A large screen in front of your body may help spread the radiation evenly.
Monitoring. Your therapist leaves the room but watches you and can talk with you through an intercom.
Treatment. The linear accelerator delivers the radiation.
Your first session may take longer because your therapist takes extra X-rays to check your position. [1] You may be able to listen to music to help the time pass. [1]
Total body irradiation at a glance
Question | Typical answer |
Length of each session | Up to 60 minutes |
Sessions per day | Up to two or three |
Number of days | Up to three to five |
Hospital stay | Often several days |
Does it hurt? | No |
Who sets your schedule? | Your care team, before treatment starts |
Source for all rows: [1]
Is total body irradiation painful?
Total body irradiation is not painful. [1] You cannot feel the radiation beams, and the machine does not touch you during treatment. Some side effects after treatment can be uncomfortable, but they usually do not last long. [1]
What are the side effects of total body irradiation?
Total body irradiation often causes short-term side effects that begin a few days or weeks after treatment, and can cause long-term effects that show up much later. [1] How strongly you are affected depends on the number of treatments, the radiation dose and your overall health. [1]
Type | How common | Examples |
Short-term effects | Common, start days to weeks after treatment | Nausea or vomiting, diarrhea, fatigue, hair loss, headaches, itchy or discolored skin |
Low blood cell counts | Common | Higher risk of infection, bleeding (nosebleeds, bleeding gums) and anemia |
Long-term effects | Common, may appear months to years later | Cataracts, infertility, lung scarring (pulmonary fibrosis), underactive thyroid (hypothyroidism) |
Sources: [1]
The drop in blood cell counts is known as bone marrow suppression. You can read more in our guide to myelosuppression.
Does total body irradiation raise the risk of another cancer?
A bone marrow transplant raises the risk of developing a second type of cancer later in life. [1] However, that risk is lower than the health risks of not having the transplant. [1] Ask your care team how this applies to your situation.
How can you care for yourself after total body irradiation?
Caring for yourself after total body irradiation means managing side effects and giving your body time to rest. [1] These steps can help:
Ask your care team for anti-nausea medicine if you need it.
Follow your skin care instructions and moisturize regularly.
Aim for about eight hours of sleep each night.
Take time off work to rest after leaving the hospital, if you can.
Talk about how you feel with a therapist or a trusted loved one.
Consider joining a support group.
When should you call your doctor after total body irradiation?
Call your healthcare provider if you notice any sign of a complication during or after total body irradiation. [1] Warning signs include:
Fever
Chills
Skin changes, such as blisters or peeling
Because TBI lowers your blood counts and raises your risk of infection, report these signs promptly. [1]
Conclusion
Total body irradiation is a short, carefully planned course of whole-body radiation that gets your body ready for a bone marrow or stem cell transplant. It uses smaller doses than other radiation therapy, it does not hurt, and most side effects fade after treatment. Knowing the steps ahead, from the planning visit to recovery, can make the process feel far less overwhelming. If you have concerns, bring them to your radiation oncologist before treatment begins.
Preparing for a transplant? Read our full guide to stem cell transplants: types, risks and recovery next, and explore more clear, doctor-reviewed cancer care guides on rinnit.com.
FAQ
Is total body irradiation the same as chemotherapy?
No. Total body irradiation uses radiation from a machine, while chemotherapy uses drugs. The two are often given together to prepare for a bone marrow or stem cell transplant. [1]
How many sessions of total body irradiation will I need?
Most people have total body irradiation up to two or three times a day for up to three to five days. Your care team confirms the exact number of sessions before treatment starts. [1]
Will I stay in the hospital for total body irradiation?
Many people stay in the hospital for several days while receiving total body irradiation. After discharge, taking time off work to rest can help your recovery. [1]
Will I lose my hair after total body irradiation?
Hair loss is a common short-term side effect of total body irradiation. Short-term side effects usually start a few days or weeks after treatment and do not usually last long. [1]
Are the skin marks from total body irradiation permanent?
The skin marks made during the planning visit may be permanent, but they are tiny. The marks help your therapist place you in the same position for every session. [1]
Can total body irradiation affect fertility?
Infertility is a common long-term side effect of total body irradiation, so ask about fertility preservation before treatment begins. Ask your care team about your personal risk before treatment begins. [1]
Why does total body irradiation use smaller doses than other radiation therapy?
Total body irradiation spreads small doses across the whole body, while other radiation therapy aims larger doses at one area. Newer techniques also help limit the effect on healthy tissue. [1]
Does total body irradiation hurt?
No. The radiation itself is painless, and you cannot see or feel it. Holding still in position can feel uncomfortable, and your care team will help you stay as comfortable as possible.
Will I feel sick after total body irradiation?
Nausea, vomiting, diarrhea and tiredness are common around the time of treatment. Your care team can give medicine to prevent and ease nausea.
What are the long-term side effects of total body irradiation?
Late effects can include cataracts, thyroid problems, lung problems, fertility problems and a higher risk of another cancer years later. Regular follow-up visits help find and treat these early.
Related Reading
Stem Cell Transplant (Bone Marrow Transplant): Types, Risks, and Recovery explains the transplant that total body irradiation prepares you for.
Allogeneic Stem Cell Transplant: Process, Risks and Recovery describes transplants using donor stem cells and their risks.
Acute Lymphocytic Leukemia: Symptoms, Diagnosis, Treatment and Support covers a blood cancer often treated with a transplant after TBI.
Radiation Therapy: Types, How It Works and Side Effects explains how radiation therapy works and its common side effects.
References
Cleveland Clinic. Total Body Irradiation: Procedure, Benefits & Side Effects. Cleveland Clinic. Last updated November 6, 2023. https://my.clevelandclinic.org/health/treatments/17565-total-body-irradiation
Wong JYC, Filippi AR, Dabaja BS, et al. Total Body Irradiation: Guidelines from the International Lymphoma Radiation Oncology Group (ILROG). Int J Radiat Oncol Biol Phys. 2018;101(3):521-529. PMID 29893272. https://doi.org/10.1016/j.ijrobp.2018.04.071
Peters C, Dalle JH, Locatelli F, et al. Total Body Irradiation or Chemotherapy Conditioning in Childhood ALL: A Multinational, Randomized, Noninferiority Phase III Study. J Clin Oncol. 2021;39(4):295-307. PMID 33332189. https://doi.org/10.1200/JCO.20.02529
Khimani F, Dutta M, Faramand R, et al. Impact of Total Body Irradiation-Based Myeloablative Conditioning Regimens in Patients with Acute Lymphoblastic Leukemia Undergoing Allogeneic Hematopoietic Stem Cell Transplantation: Systematic Review and Meta-Analysis. Transplant Cell Ther. 2021;27(7):620.e1-620.e9. PMID 33798768. https://doi.org/10.1016/j.jtct.2021.03.026
Ansari F, Behfar M, Jafari L, et al. A comprehensive comparison between TBI vs non-TBI-based conditioning regimen in pediatric patients with acute lymphoblastic leukemia: A systematic review and meta-analysis. Leuk Res. 2023;135:107416. PMID 37918224. https://doi.org/10.1016/j.leukres.2023.107416
Medical disclaimer
This article is for general education only and does not replace advice from your doctor or care team. Treatment plans for total body irradiation differ from person to person, so always follow the instructions of your healthcare providers. If you have a fever, chills or other warning signs during or after treatment, contact your care team or seek emergency care right away.
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