Radiation Therapy

Some, but not all, patients undergoing a bone marrow transplant benefit from the use of total body irradiation, a form of radiation therapy. This is called TBI for short, and it is given to the entire body either before or after chemotherapy and before bone marrow transplantation. Radiation does two things: It kills cancer cells and it suppresses or holds back the immune system, allowing the healthy transplanted cells, or the graft, to “take.”

Here’s how TBI works:

The radiation is given from a radiation machine that contains a linear accelerator. This specially designed, computerized equipment makes it easier for radiation oncologists — the physicians who specialize in radiation therapy — to create tailored treatment for individual patients.
During the radiation treatment, the patient is kept in a constant position within a brace. The patient sits on a bicycle-type seat while undergoing radiation. An alternative is for the patient to lie down during the treatment. We prefer to have the patient standing up because the blood supply to the lungs is more consistent in this position and that affects the radiation dose.

The patient is then helped into the brace and the radiation is given.

Outside the room, the operator observes the patient via a video camera monitor and administers radiation. Microphones allow the patient and the operator to communicate throughout the entire procedure.

There are different types of schedules for giving radiation — in other words, how often a patient undergoes radiation depends on the individual. The usual regimen is to receive radiation twice a day for a total of six doses. The lungs are shielded from radiation for one or more doses, because the lungs are more sensitive to the effects of radiation than the rest of the body. Each procedure lasts about half an hour. Most people tolerate the radiation well except for some skin redness, occasional hiccups and nausea toward the end of the treatment. Usually the side effects are controlled well with medication. Other side effects occur later — these include a drop in white blood cell count and mouth ulcers.

For more information about bone marrow/stem cell care visit the home page for the Bone Marrow Transplant Center at Rush University Medical Center in Chicago, Illinois.