In vivo dosimetry in the pelvis during fast neutron therapy.

Abstract

The assessment of dose distributions in patients during treatment with fast neutrons is based on measurements in a phantom material, i.e. water or another type of tissue equivalent (TE) liquid. Only limited information is available on fast neutron dosimetry in vivo in order to check how well these phantom materials simulate the average density and composition of the human body in the irradiated area. At Hammersmith Hospital, in-vivo dosimetry has been applied to check the dose in the oesophagus as well as the exit dose during irradiation of carcinoma of the bronchus (Field, 1971). Activation of small pellets of aluminium and measurement of the induced 27Mg activity was the technique used. More recently the application of CaSO4: Tm phosphor TLD (Blum et al., 1976) and the activation of indium (Catterall and Bewley, 1979) have been described for dosimetry during neutron therapy in that institute. Smith et al. (1976) inserted silicon diodes into the oesophagus to measure the effect of intervening lung tissue...