A THEORETICAL MODEL FOR THE STUDY OF NEUTRON EFFECTS ON TUMORS

Aspects of neutron radiotherapy for tumnors are presented fromn an entirely theoretical point of view. A model is proposed assuming: loss of reproductive integrity is some portion of the tumor mass; limitation of the effects to a specific tumor mass; exhibition by the tumor cells of a multibit survival curve; continuation past the survival curve shoulder in an indefinite exponential trend; interpretation of recovery as damage recuperation at the cellular level; application of observed irradiated phenomena in free cells to tumor masses; time intervals between radiation doses sufficient for maximumn possible recovery; and a recovery rate independent of linear energy transfer. From a purely theoretical analysis and in the absence of experimental data on the subject, it was impossible to make predictions of immediate practical value. It seemed possible to anticipate, however, that necrotic tumors with an insufficient blood supply would be particularly responsive to neutron treatment. In special cases, when the state of oxygenation of the cells may be thought to improve during fractionated therapy, a mixed treatment could also be considered. (H.M.G.)