Total body irradiation

Total body irradiation (TBI) is a form of radiotherapy used primarily as part of the preparative regimen for hematopoietic stem cell (or bone marrow) transplantation. As the name implies, TBI involves irradiation of the entire body, though in modern practice the lungs are often shielded to a certain degree to lower the risk of radiation-induced lung injury.

History

The use of TBI as a treatment modality dates back to the mid-20th century, with the first reported use in humans in the 1950s. It was initially used in the treatment of Hodgkin's disease and leukemia, and later found its primary application in the field of bone marrow transplantation.

Procedure

TBI is typically delivered in several fractions, or doses, over a few days. This is done to minimize the side effects of the radiation. The patient is positioned at a certain distance from the radiation source to ensure even distribution of the radiation dose. The dose and schedule of TBI may be adjusted based on the patient's age, overall health, type of transplant, and the specific disease being treated.

Applications

The main application of TBI is in the field of hematopoietic stem cell transplantation. It is used as part of the preparative regimen to eradicate the patient's own bone marrow and immune system before the transplant. This helps to prevent rejection of the transplanted cells and also to kill any remaining cancer cells in the body.

TBI is also used in the treatment of certain non-malignant disorders, such as severe aplastic anemia, where it can be used to destroy the patient's bone marrow before a transplant.

Side effects

As with any form of radiation therapy, TBI can have side effects. These can include nausea, vomiting, diarrhea, skin changes, fatigue, and an increased risk of infections due to the effect of the radiation on the immune system. Long-term side effects can include infertility, cataracts, secondary cancers, and damage to the lungs, kidneys, or liver.

See also

• Radiotherapy
• Bone marrow transplantation
• Hematopoietic stem cell transplantation
• Radiation therapy