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Why is total body irradiation used before some bone marrow transplants?
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radiation therapy
External beam radiation therapy (also known as external beam teletherapy, or long-distance therapy) being delivered using a machine known as a linear accelerator.
Total body irradiation is used as a preparatory step before a bone marrow transplant primarily to destroy defective or diseased tissue within the patient.12
By delivering a dose of approximately 10 gray, this process causes the complete cessation of bone marrow development. This serves two critical functions:2
- Eliminating Disease: It helps eradicate malignant or defective cells, such as those found in patients with leukemia.12
- Preventing Rejection: It suppresses the recipient's immune system, which reduces the patient's ability to develop antibodies against the donor's "foreign" cells. This creates a receptive environment that allows the transplanted marrow cells to migrate to the marrow spaces, where they can proliferate and repopulate the blood-forming tissues.3
In addition to irradiation, immunosuppressive drugs are often used in conjunction to further prepare the recipient and minimize the risk of graft-versus-host disease.1