Investigation of dose homogeneity in paediatric anthropomorphic phantoms for a simple total body irradiation technique.

The technique for treating total body irradiation patients used at the centre involves no compensation for the inhomogeneity of patient shape. Dose is prescribed to the lung, and monitor units are derived from standard data depending on the external dimensions of the patient at nipple level. Dose measurements were made during standard treatments on three paediatric anthropomorphic phantoms representing children of 5, 10 and 15 years of age. The results confirmed that the measured dose to the lung was within 4% of the prescribed dose, and dose homogeneity was within +/- 5%, excluding the neck, where the higher measured doses were still within tissue tolerance.