Fractionated total body irradiation in bone marrow transplantation - an emphasis on lung dosimetry

The use of fractionated total body irradiation is now replacing the large single dose technique originally used in many centres. Twenty-three patients have received this form of therapy prior to marrow transplantation at St. Vincent's Hospital. Doses of 12 to 14 Gray are delivered over 3 to 3 and 1/2 days treating twice daily. Particular emphasis is placed on the amount of radiation received by the lungs and the prescribed dose is related directly to this. The rationale of this technique is discussed, together with the methods of dose calculation, set-up, and incidence of side effects. Fractionation results in a regime that is very well tolerated with a lower morbidity than that seen with single dose irradiation