Dose Evaluation of Patients Receiving Total-Body Irradiation for the Pre-Treatment of Bone Marrow Transplantation

In a total-body irradiation (TBI), an absorbed dose of around 10 Gy is given to a patient with leukaemia within a couple of days. Delivery of a homogeneous dose throughout the whole body is difficult, and usually requires sophisticated irradation techniques. It is important to evaluate patient doses experimentally both for physical treatment planning and radiological protection. Organ and surface doses of patients were evaluated for a newly employed TBI technique - modified tracking technique. An experiment with a RANDO phantom demonstrated a good dose distribution over the whole body. Measurement of patient doses, however, revealed a variation of the doses between patients. Reproducibility of patient set-up is considered to be a critical factor for the variation, and improvement is desirable in this regard.