Technique and dosimetry of total body irradiations at Ulm.

At the University of Ulm total body irradiation before bone marrow transplantation is given in nine fractions within three days. A total dose of 13 Gy is applied via four fields with 8-MV X-rays. Dose to the lung is limited to 10.5 Gy by means of individually shaped blocks. The homogeneity of dose distributions is improved by the use of compensators for the lower extremities and boli in the head and neck region. Dosimetric data for treatment planning are measured by an ionization chamber and thermoluminescence dosimeters in water and perspex phantoms. In vivo measurements of dose distributions (ionization chamber, TLD) during each fraction allow modifications of compensators and boli in the case of deviations from calculated data.