In vivo measurements of lung corrections for fast-neutron therapy

Silicon diodes were inserted into the esophagus and bronchus of anesthetized rhesus monkeys in order to measure the corrections to tumor dose resulting from intervening lung tissue during fast-neutron therapy. The derived corrections were applied to tumor doses for patients being treated for cancer of the esophagus on the fast-neutron beam at TAMVEC. In vivo dosimetry performed on these patients using silicon diodes in the esophagus confirmed the accuracy of the lung corrections. The measured dose and calculated dose agreed to within 4% for four different patients. Tha magnitude of the correction is on the order of 16% for the typical esophageal cancer patient. These studies were also done with Cobalt-60 in order to test, against other data, the results obtained with this animal model.