The dosimetry of 60Co total body irradiation.

The dosimetry characteristics of a single source ⁶⁰Co total body irradiation (TBI) facility have been studied. The dose distribution for AP-PA irradiation in an adult size and an infant size phantom was measured in detail using thermoluminescent dosimeters. A 10% homogeneity relative to the midline dose was found over most of the body. An increase of 10% relative to midline dose was noted in the thoracic region because of lower density lung tissue. A relative decrease of more than 10% was found in the head region because of the reduced beam intensity away from the central axis and reduced scatter volume. Dose in the abdomen was homogeneous to ± 5%.