Total Body Irradiation (TBI): The Lifesaving Radiation Before Bone Marrow Transplants

Imagine a treatment that prepares your entire body for a life-saving procedure—Total Body Irradiation (TBI) does just that. TBI is a crucial step before bone marrow transplants, giving patients with leukemia, lymphoma, and other serious conditions a better chance at recovery. But what exactly is TBI, and why is it so important?

What Is Total Body Irradiation?
TBI involves delivering radiation to the entire body. This process is essential because it (i) destroys cancer cells within the bone marrow, further makes space for the transplanted cells (ii) radiation weakens the immune system, reducing the risk of the body rejecting the donor's bone marrow. At star hospitals under the expert care of specialists like Dr. Chinna Babu Dracham, Senior Consultant & Head of Radiation Oncology, the TBI has now become a key part of modern cancer treatment, offering hope to many.
What Is Radiation Therapy?
Radiation therapy is one of the oldest and most widely used treatments for cancer. It uses high-energy X-rays to target specific body parts, aiming to destroy cancer cells while sparing healthy tissue. This method has been around since the 1896s and has evolved significantly, now allowing precise doses to be delivered to tumors with minimal impact on surrounding tissues.
But did you know that despite being a powerful tool against cancer, radiation therapy does not make patients radioactive? This means they can safely be around their loved ones during treatment.
Understanding Total Body Irradiation (TBI)
Why do doctors use TBI before a bone marrow transplant? TBI is an essential part of the conditioning regimen that prepares the body for this life-saving procedure. It works with chemotherapy to damage cancer cells throughout the body, including those hiding in the bone marrow. This dual approach increases the chances of a successful transplant. The purpose is to destroy cancer cells within the bone marrow and make space for the transplanted cells, which is called myeloablative therapy.
TBI is particularly valuable in treating conditions like leukemia (acute lymphoid leukemia and acute myeloid leukemia), multiple myeloma, and lymphoma (Hodgkins and Non-Hodgkins). Interestingly, it’s also used for certain non-cancerous conditions, such as aplastic anaemia, myelproliferative disorders, and sickle cell anaemia, during transplants.
How Is TBI Delivered?
There are two main techniques for delivering TBI:
• Conventional TBI: In this method, the patient lies down or stands at a distance from the radiation source-to-skin distance (SSD) (radiation source to the patient skin surface). While effective, this technique can have drawbacks, such as reduced dose rates and challenges in sparing critical organs.

• Conformal TBI (VMAT-TBI): This is a more advanced and precise technique. Patients lie comfortably on a treatment couch, and the radiation is delivered at standard SSD with greater accuracy, ensuring uniform dose coverage and protecting vital organs.
What Happens During TBI Treatment?
Here’s what you can expect:
• Immobilization: You’ll be positioned using a special molded bag or mask to keep you still during treatment.
• CT Simulation: A detailed scan of your body is taken before the radiation therapy.
• Targeting the Right Areas: Doctors carefully map out where to direct the radiation, focusing on treating the cancer while protecting organs like the lungs and kidneys.
• Radiation Planning: The treatment plan is optimized, verified and approved to get uniform dose coverage of your body, ensuring the radiation is delivered as accurately as possible.
• Treatment Delivery: Once everything is set, the radiation is delivered to a phantom for precision and then delivered to the patient under strict aseptic conditions.
What Is the Treatment Schedule?
TBI can be delivered in a single session or split into two sessions, six hours apart on the same day. Sometimes, it spreads over multiple days, depending on the patient’s needs.
How long does a typical TBI treatment delivery take?
Depending upon the schedule and the technique of TBI, the treatment delivery time typically is about 60 minutes to 100 minutes per session.
Potential Side Effects of TBI
While TBI is a powerful treatment, it can cause side effects like nausea, fatigue, vomiting, mucositis (inflammation and ulcers inside the mouth), and diarrhoea. These usually appear immediately or three days after the treatment. The causes for these symptoms are multifactorial such as chemotherapy and transplant related.  However, with modern protocols, serious side effects like pneumonitis (lung inflammation) and nephrotoxicity (kidney damage) are rare.
A Team Effort for Success
Delivering TBI safely and effectively requires a highly skilled team of radiation oncology professionals. With the latest advancements in radiation planning and technology, TBI has become an efficient way to control bone marrow disease and reduce the risk of graft rejection.
Is TBI the right approach for everyone facing a bone marrow transplant? Discussing these options with your healthcare provider can provide more personalized information and help guide your treatment journey.

Dr. Chinna babu – Dracham,  MBBS, MD (Radiation Oncology),PGIMER Chandigarh, ECMO Senior Consultant & Head of Radiation Oncology. STAR hospital  Hyderabad

For more details please visit

www.starhospitals.in